Mi hija abraza su peluche como si fuera su mejor amiga.

In modern Spanish, possessive adjectives like mi, tu, su, nuestro usually go directly before the noun, without an article:

• mi hija = my daughter
• tu casa = your house

Using an article plus a possessive in this position is not normal in standard modern Spanish. So mi hija is the natural way to say my daughter.

Abraza comes from the verb abrazar, which means to hug or to hold in an embrace.

Here:

• Mi hija abraza... = My daughter hugs...

It is:

• present tense
• third person singular
• because the subject is mi hija = she

So:

• yo abrazo = I hug
• tú abrazas = you hug
• él/ella abraza = he/she hugs

Peluche usually means a stuffed toy / plush toy. Depending on context, it can sometimes be translated as:

• stuffed animal
• plushie
• soft toy
• sometimes teddy bear, if that is the specific toy meant

So su peluche is not necessarily a bear. It is more general than teddy bear.

Su can mean:

• his
• her
• its
• your (formal singular)
• their

Spanish does not distinguish these in the possessive adjective the way English does.

In this sentence:

• su peluche most naturally means her stuffed toy (the daughter’s toy)
• su mejor amiga most naturally means her best friend (again referring to the daughter)

So the meaning is understood from context, even though su by itself is ambiguous.

If you needed to make it extra clear, Spanish can use:

• el peluche de mi hija
• la mejor amiga de mi hija

After como si (as if), Spanish normally uses the imperfect subjunctive.

That is why we get:

• como si fuera = as if it were / as though it were

The verb here is ser, and fuera is the imperfect subjunctive form.

This is a very important pattern:

• Habla como si lo supiera. = He speaks as if he knew it.
• Me mira como si estuviera enfadado. = He looks at me as if he were angry.

So in your sentence:

• Mi hija abraza su peluche como si fuera su mejor amiga.
• literally: My daughter hugs her stuffed toy as if it were her best friend.

Even though the main verb is in the present (abraza), como si still triggers the imperfect subjunctive.

Fuera is the imperfect subjunctive of ser.

Conjugation of ser in the imperfect subjunctive:

• yo fuera
• tú fueras
• él/ella fuera
• nosotros fuéramos
• vosotros fuerais
• ellos fueran

Here, the subject of fuera is su peluche:

• su peluche ... fuera su mejor amiga
• her stuffed toy ... were her best friend

So fuera agrees with a singular subject.

Because amiga refers to a female friend.

The sentence says:

• su mejor amiga = her best friend (female)

This matches the idea that the daughter is treating the toy as if it were a girl friend, not just a friend in general.

Compare:

• su mejor amigo = her best male friend / his best male friend
• su mejor amiga = her best female friend / his best female friend

Since hija is female, it is natural that best friend is also expressed as amiga, though that depends on the intended meaning, not grammar alone.

Because mejor is an invariable comparative adjective here. It does not change for gender.

So you say:

• el mejor amigo
• la mejor amiga
• los mejores amigos
• las mejores amigas

It changes for number (mejor / mejores), but not for masculine vs feminine in the singular form.

Possessive adjectives usually replace the article.

So Spanish says:

• su mejor amiga = her best friend not
• la su mejor amiga

This is the same pattern as:

• mi casa = my house
• tu hermano = your brother
• su mejor amiga = her best friend

Normally, no. With abrazar, you usually do not use the personal a when the object is a thing or animal treated as a thing.

So:

• abraza su peluche is the normal phrasing

The personal a is mainly used before specific people, and sometimes pets or personified beings.

For example:

• Abraza a su madre. = She hugs her mother.
• Abraza a su perro. = She hugs her dog.
  (possible, because it is an animal and often treated personally)

But peluche is an object, so abraza su peluche is the standard choice.

No. It expresses a comparison or imagined situation:

• as if it were her best friend
• as though it were her best friend

The structure suggests that the toy is not literally her best friend, but she is hugging it in that way.

This is exactly why Spanish uses the subjunctive: it presents something hypothetical, imagined, or contrary to reality.

Yes. Fuera and fuese are both valid imperfect subjunctive forms of ser.

So these are both correct:

• como si fuera su mejor amiga
• como si fuese su mejor amiga

In everyday Spanish, fuera is usually more common.

Although fuera looks like a past form, here it is not functioning as a normal past tense. It is the imperfect subjunctive, which is required after como si.

So the time reference of the sentence is still present because of abraza:

• Mi hija abraza... = My daughter hugs...

And then:

• como si fuera... = as if it were...

This is a fixed grammatical pattern in Spanish. The imperfect subjunctive after como si does not necessarily mean the action happened in the past.

The subject of fuera is su peluche.

Structure:

• Mi hija = subject of abraza
• su peluche = direct object of abraza
• in the comparison clause, su peluche becomes the understood subject of fuera

So the meaning is:

• My daughter hugs her stuffed toy as if the stuffed toy were her best friend.

Not:

• as if my daughter were her best friend

The context makes that clear.

Yes, it sounds natural. It uses very normal Spanish:

• Mi hija abraza... = straightforward present tense
• su peluche = common vocabulary
• como si fuera... = very common structure for as if

A native speaker would understand it easily and it sounds idiomatic.