Mi padre tiene la misma manía con las llaves y siempre mira si están en su bolsillo.

In modern Spanish, you normally use a possessive adjective like mi, tu, su, etc. without an article before family members and most nouns:

• mi padre = my father
• mi coche = my car

Using el mi padre is not standard modern Spanish.

Also, Spanish often uses mi padre where English might say my dad or my father. Padre is neutral; papá would sound more like dad.

Because misma has to agree with manía, which is:

• feminine
• singular

So:

• la misma manía = the same habit/obsession
• el mismo problema = the same problem
• las mismas llaves = the same keys

The word mismo/a/os/as usually comes before the noun in this expression:

• la misma idea
• el mismo día

Here, manía does not usually mean a serious medical condition. In everyday Spanish, it often means something like:

• a quirk
• a fixation
• a habit
• a thing someone is fussy or obsessive about

So tener manía con algo can mean someone is overly preoccupied with it.

In this sentence, it suggests the father has a repeated, slightly obsessive habit concerning the keys.

Here con means something like about or regarding, not just with in the literal sense.

So:

• tener una manía con las llaves = to have a hang-up / obsession / particular habit about the keys

Spanish often uses the definite article where English might use a possessive or nothing at all. Las llaves here means the keys, but in context it really means his/the keys he uses.

Yes, mirar literally means to look, but it can also mean to check or to see whether in many contexts.

So:

• mira si están en su bolsillo = he checks whether they are in his pocket

This is very natural Spanish. It is not just looking in a general sense; it implies verifying something.

Here si means whether or if.

• mira si están en su bolsillo = he checks if/whether they are in his pocket

This si has no accent.

Be careful not to confuse it with sí with an accent, which means:

• yes
• or himself/herself in some expressions

So:

• si = if/whether
• sí = yes

Because están refers to las llaves, which is plural.

• la llave está = the key is
• las llaves están = the keys are

Even though las llaves is not repeated in the second part, it is still the subject understood from context:

• si están en su bolsillo = if they are in his pocket

Spanish often leaves out subject pronouns when they are clear from the verb form or context.

So instead of saying:

• si ellas están en su bolsillo

Spanish normally just says:

• si están en su bolsillo

Because están already tells you the subject is plural, and context tells you it refers to las llaves.

Both patterns can exist in Spanish, but here su bolsillo is perfectly natural because it clearly means his pocket.

• su bolsillo = his/her/your pocket (depending on context)

Spanish often uses possessives when the owner matters or helps clarity.

You may also see Spanish use the definite article with body parts or clothing in other structures, especially when the owner is already obvious:

• Se metió la mano en el bolsillo. = He put his hand in his pocket.

But in your sentence, en su bolsillo sounds very normal and clear.

Because the sentence is talking about checking one pocket, not pockets in general.

• en su bolsillo = in his pocket

If the idea were that he checks more than one, Spanish could use:

• en sus bolsillos = in his pockets

But with keys, it is very common to imagine one usual pocket, so the singular sounds natural.

Yes. Grammatically, su can mean:

• his
• her
• your (formal singular)
• their
• your (plural, in Spain usually formal)

But in this sentence, context makes it clear that su bolsillo refers to his pocket, meaning the father’s.

If Spanish needs to remove ambiguity, it can say:

• el bolsillo de mi padre

But that is less natural here because the context already makes it obvious.

That is the normal position for an adverb like siempre:

• siempre mira = he always checks/looks

Spanish adverbs are flexible, but siempre commonly goes before the verb:

• siempre llega tarde
• siempre dice eso

You could move it for emphasis in some contexts, but siempre mira is the most neutral order here.

Yes, absolutely.

Both are natural:

• Mi padre tiene la misma manía con las llaves y siempre mira si están en su bolsillo.
• Mi padre tiene la misma manía con las llaves y mira siempre si están en su bolsillo.

But siempre mira sounds more natural than mira siempre in this sentence.

You could also move siempre earlier:

• Mi padre siempre tiene esa manía...

That slightly changes what always is modifying, though. In your original sentence, always specifically goes with the checking action.

Because Spanish often uses the present tense to describe habitual actions:

• siempre mira = he always checks
• todos los días sale temprano = he leaves early every day

So this is not just about what he is doing right now. It describes something he does regularly.

Because buscar means to look for something, usually when you do not know where it is.

• buscar las llaves = to look for the keys

But mirar si están en su bolsillo means to check whether they are in his pocket.

So the difference is:

• buscar = search for
• mirar si... = check whether...

In this sentence, he is not necessarily doing a full search; he is verifying that the keys are there.