Mein Bruder tut so, als habe er keine Zeit, aber am Ende hilft er mir doch beim Aufräumen.

After als in this meaning (as if), German often uses Konjunktiv I or Konjunktiv II to show that something is only apparent, assumed, or not necessarily true.

So:

• als habe er keine Zeit = as if he had no time

Here, habe is Konjunktiv I of haben.

Why not hat?
Because hat is the normal indicative form and sounds more like a straightforward statement of fact. In this sentence, the speaker is saying that the brother only acts as if he has no time.

In everyday German, many speakers also use als ob + indicative or als würde ..., for example:

• Mein Bruder tut so, als ob er keine Zeit hat.
• Mein Bruder tut so, als würde er keine Zeit haben.

All are possible, but als habe er is a bit more formal or written-style.

So tun, als ... means to pretend, to act as if, or to give the impression that.

In this sentence:

• Mein Bruder tut so, als habe er keine Zeit
  = My brother acts as if he has no time

It is a very common structure in German.

You can use it with different subjects:

• Er tut so, als wüsste er alles.
• Sie tut so, als wäre sie überrascht.

A useful way to remember it is:

• so tun, als ... = to behave as though ...

In the clause after als, the verb comes first because this is a subordinate clause with a special structure using the subjunctive.

So you get:

• als habe er keine Zeit

The order is:

• als
  • conjugated subjunctive verb + subject + rest

This is especially common in more formal German after als in this kind of comparison.

Compare:

• als habe er keine Zeit
• als wäre sie krank
• als wüsste niemand etwas

If you use als ob, then the verb goes to the end like in a more typical subordinate clause:

• als ob er keine Zeit hätte
• als ob sie krank wäre

So both are correct, but the structures are different.

There are two commas for two different reasons.

1. Comma before the subordinate clause
   In tut so, als habe er keine Zeit, the part starting with als is a subordinate clause, so it must be separated by a comma.

   • Mein Bruder tut so, als habe er keine Zeit

2. Comma before coordinating conjunctions like aber
   German normally uses a comma before aber when it links two main clauses.

   • ..., aber am Ende hilft er mir doch beim Aufräumen.

So the commas are standard punctuation, not optional stylistic choices.

Here, doch means something like:

• after all
• actually
• in the end anyway
• contrary to what it seemed

In this sentence, it shows a contrast between appearance and reality:

• He acts like he has no time,
• but actually / in the end he does help me

So:

• ... aber am Ende hilft er mir doch beim Aufräumen.

This doch adds the sense of despite that impression.

German doch is very flexible, so it does not always translate with one fixed English word. In this sentence, it signals that the second part goes against what the first part made you expect.

In this sentence, am Ende means in the end or eventually.

• am Ende hilft er mir doch ...
  = in the end he does help me ...

This is not the same as endlich.

• am Ende = at the end of the situation / finally, after everything
• endlich = finally, often with a feeling of relief, impatience, or satisfaction

Examples:

• Am Ende hilft er mir doch.
  = In the end, he does help me.

• Endlich hilft er mir!
  = He’s finally helping me!
  (This sounds more emotional.)

So am Ende is the more neutral choice here.

The verb helfen takes the dative, not the accusative.

So:

• jemandem helfen = to help someone

That means:

• mir = dative of ich
• not mich (accusative)

Examples:

• Er hilft mir.
• Ich helfe dir.
• Wir helfen unserem Freund.

This is something English speakers often have to memorize, because English help someone does not show the case difference.

Beim Aufräumen means with the tidying up, while tidying up, or more naturally in English here, with the cleaning up / tidying up.

It is made from:

• bei dem → beim
• Aufräumen = the verbal noun from aufräumen (to tidy up)

So literally:

• beim Aufräumen = during the tidying up / in the process of tidying up

After helfen, this structure is very common:

• jemandem beim Kochen helfen = help someone with cooking
• jemandem beim Lernen helfen = help someone with studying
• jemandem beim Aufräumen helfen = help someone with tidying up

It is often more natural in German than trying to build an infinitive construction.

Because here Aufräumen is being used as a noun.

German often turns verbs into nouns, and those are capitalized:

• aufräumen = to tidy up
• das Aufräumen = the tidying up / tidying

In the phrase beim Aufräumen, the word comes after the preposition bei and article dem, so it is functioning as a noun.

Other examples:

• beim Essen = while eating / during the meal
• beim Arbeiten = while working
• beim Fahren = while driving

This is a very common pattern in German.

This is because German main clauses follow the verb-second rule.

In a main clause, the finite verb usually comes in the second position. Whatever comes first can be:

• the subject
• a time expression
• an object
• another element

Here, am Ende is placed first, so the verb must come next:

• aber | am Ende | hilft | er | mir | doch | beim Aufräumen

If the subject were first, it would be:

• Aber er hilft mir am Ende doch beim Aufräumen.

That is also possible, but it gives a slightly different emphasis. With am Ende first, the sentence emphasizes the eventual outcome.

Yes, in everyday spoken German many people would say:

• Mein Bruder tut so, als ob er keine Zeit hat ...

That is very common and natural.

However, with the structure actually used here:

• als habe er keine Zeit

the subjunctive gives a more polished, slightly more literary or formal tone.

So these are all possible, with slightly different styles:

• als habe er keine Zeit → concise, somewhat formal/written
• als ob er keine Zeit hätte → standard, very common
• als ob er keine Zeit hat → common in speech, less formal/less strict
• als würde er keine Zeit haben → also common, especially in speech

A learner should recognize all of them.

German uses kein to negate nouns that do not have a definite article.

So:

• Zeit here is a noun with no article
• therefore German says keine Zeit

Compare:

• Ich habe Zeit. = I have time.
• Ich habe keine Zeit. = I have no time.

You would use nicht in other situations, for example:

• to negate a verb: Ich komme nicht.
• to negate an adjective: Das ist nicht wichtig.
• to negate a definite noun phrase: Ich habe die Zeit nicht.

So in this sentence, keine Zeit is exactly what you would expect.

Yes. Mein Bruder is the subject of the main clause, so it is in the nominative.

Breakdown:

• mein = my
• Bruder = brother

Because Bruder is masculine and nominative singular, mein stays in the form mein.

If the case changed, the form would change too:

• nominative: mein Bruder
• accusative: meinen Bruder
• dative: meinem Bruder

In this sentence, though, it is simply the subject doing the action:

• Mein Bruder tut so ...

Yes, the sentence would still be grammatically correct without it:

• Mein Bruder tut so, als habe er keine Zeit, aber am Ende hilft er mir beim Aufräumen.

Without doch, the sentence is more neutral.
With doch, it more clearly highlights the contrast between what he seems to be doing and what he actually does.

So doch is not required for grammar, but it adds an important nuance:

• surprisingly
• contrary to appearances
• after all

That is why it sounds very natural here.