Ο σύντροφός της είναι ήρεμος άνθρωπος και τη βοηθάει πολύ όταν έχει άγχος.

In this sentence, σύντροφος most naturally means partner.

It is a fairly broad word and can refer to:

• a romantic partner
• a live-in partner
• sometimes a spouse
• in other contexts, even companion or comrade

So ο σύντροφός της is best understood as her partner. The exact English word depends on context.

The basic dictionary form is indeed σύντροφος.

The extra accent in σύντροφός της appears because της is an enclitic: a little unstressed word that leans on the word before it. When a word like σύντροφος is stressed on the third-to-last syllable, Greek often adds a second written accent before an enclitic:

• σύντροφος
• ο σύντροφός της

This does not mean the word has changed form in the dictionary sense. It is mainly a stress/spelling rule triggered by the following clitic.

Yes, they both relate to her, but they do different jobs.

• της in ο σύντροφός της means her as a possessive:
  her partner
• τη in τη βοηθάει means her as a direct object:
  he helps her

So:

• της = her / of her
• τη(ν) = her as the person receiving the action directly

Because in Modern Greek, weak object pronouns like με, σε, τον, τη, το, μας, σας, τους usually come before a finite verb.

So Greek says:

• τη βοηθάει = he helps her

not a structure like English helps her, where the object comes after the verb.

A useful pattern to remember is:

• τον βλέπω = I see him
• την ξέρω = I know her
• το θέλω = I want it

Both exist, but τη βοηθάει is very normal.

The full form is την, but the final -ν is often dropped before many consonants, especially in everyday speech and writing. Since β in βοηθάει is a consonant, τη βοηθάει is perfectly natural.

So:

• την = fuller form
• τη = very common shortened form before many consonants

You will often see both in real Greek.

Because ήρεμος agrees with the noun it describes.

Here, άνθρωπος is:

• masculine
• singular
• nominative

So the adjective must also be:

• masculine
• singular
• nominative

That gives:

• ήρεμος άνθρωπος = a calm person

Compare:

• ήρεμη γυναίκα = a calm woman
• ήρεμο παιδί = a calm child

After είναι, Greek often leaves out ένας when describing what someone is like.

So:

• είναι ήρεμος άνθρωπος = he is a calm person

is completely natural.

You could also say:

• είναι ένας ήρεμος άνθρωπος

This is also correct, but it can sound a little more explicit or slightly more emphatic. Greek often prefers the version without ένας in this kind of descriptive sentence.

Yes. In this context, βοηθάει and βοηθά are both acceptable present-tense forms meaning he/she helps.

So these are equivalent:

• τη βοηθάει πολύ
• τη βοηθά πολύ

You will hear and read both. A learner should recognize both as normal Modern Greek.

Άγχος usually means anxiety, stress, or anxious tension.

So όταν έχει άγχος literally means:

• when she has anxiety/stress

In natural English, that may become:

• when she is anxious
• when she feels stressed

Greek often uses έχω + noun where English might prefer be + adjective.

Greek often leaves out subject pronouns when they are understood from context.

So έχει literally just means he/she has. The subject is not stated, because Greek does not need to say she or he every time.

In this sentence, the most natural interpretation is:

• he helps her a lot when she has anxiety / when she is anxious

The context makes it clear that she is the one with άγχος.

Here πολύ works as an adverb and means a lot or very much.

It modifies the verb βοηθάει:

• τη βοηθάει πολύ = he helps her a lot

So it is not describing a noun here; it is describing the extent of the action.

Greek word order is more flexible than English, although some positions are more natural than others.

The original sentence is very natural:

• Ο σύντροφός της είναι ήρεμος άνθρωπος και τη βοηθάει πολύ όταν έχει άγχος.

You could move some elements for emphasis, but the clitic pronoun τη normally still stays before the finite verb:

• και πολύ τη βοηθάει όταν έχει άγχος
• όταν έχει άγχος, τη βοηθάει πολύ

So yes, word order can change somewhat, but the original version is straightforward and idiomatic.