Она позаботилась о друге.

This is an aspect question.

• заботиться = to care for / to be taking care of in an ongoing, repeated, or general sense
• позаботиться = to take care of / to make sure something is taken care of as a completed action

So:

• Она заботилась о друге = she was caring for her/the friend, she used to care for the friend
• Она позаботилась о друге = she took care of the friend, she made sure the friend was looked after

The prefix по- helps make the verb perfective, so the sentence presents the action as completed.

It contains two important pieces:

• -л- = past tense marker
• -а = feminine singular
• -сь = reflexive ending, a short form of -ся

So позаботилась means a feminine singular subject did the action in the past.

That matches она.

Compare:

• он позаботился = he took care of...
• она позаботилась = she took care of...
• они позаботились = they took care of...

No, not directly.

In this verb, -ся / -сь is just part of the normal dictionary form: позаботиться. It does not mean that she literally took care of herself.

So позаботиться о ком-то is simply the standard Russian way to say to take care of someone or to see to someone’s needs.

A good way to learn it is as a whole pattern:

• заботиться о ком-то / о чём-то
• позаботиться о ком-то / о чём-то

Because the preposition о requires the prepositional case here.

The noun changes like this:

• nominative: друг
• prepositional: о друге

So after заботиться о or позаботиться о, you say:

• о друге = about/for the friend
• о маме = about/for mother
• о детях = about/for the children

This is something you should memorize together with the verb: позаботиться о + prepositional case.

Yes, о often means about, especially after verbs of speaking or thinking:

• говорить о книге = to talk about a book

But with заботиться and позаботиться, Russian uses о in an idiomatic way. In English, the most natural translation is usually:

• care for
• take care of
• look after
• see to

So позаботилась о друге is not literally she concerned herself about a friend in normal English, even though that is close to the structure. Idiomatically, it means she took care of her/the friend.

Usually, yes.

The noun друг normally means a male friend. Its prepositional form is о друге.

If the friend were female, Russian would usually use подруга:

• Она позаботилась о подруге = She took care of her/the female friend

So this sentence most naturally suggests that the friend is male.

The verb shows gender and number, but not clearly person by itself.

позаботилась tells you that the subject is:

• feminine
• singular
• past

But without context, it could mean:

• I took care of... (if the speaker is female)
• you took care of... (addressing one female person, depending on context)
• she took care of...

So она is useful because it clearly tells you the subject is she.

In context, Russian often drops pronouns, but here она makes the sentence explicit and unambiguous.

Russian has no articles.

So о друге could mean:

• about a friend
• about the friend
• about her friend
• sometimes even just about a friend of his/hers, depending on context

You understand which one is meant from the situation, earlier sentences, or general context.

That is why one Russian sentence can correspond to several English versions.

Yes. Russian word order is more flexible than English word order.

The most neutral order here is:

• Она позаботилась о друге.

But you could also say:

• О друге она позаботилась.
• Позаботилась она о друге.

These alternatives change the focus or emphasis, not the core meaning.

For example:

• О друге она позаботилась puts extra attention on the friend
• Она позаботилась о друге is the straightforward, neutral version

Usually позаботиться о suggests a practical, completed act of care:

• making arrangements
• helping someone
• making sure someone is okay
• seeing that someone’s needs are met

It can include emotional concern, but the perfective form позаботилась often sounds like she made sure to take care of it / she saw to him.

If you want to emphasize ongoing care or a general attitude, заботилась о друге may fit better.

The standard stress is:

• Она́ позабо́тилась о дру́ге.

The stressed syllables are:

• она́
• позабо́тилась
• дру́ге

For a learner, the most important thing is to remember:

• позабо́тилась, not позаботила́сь
• дру́ге, not друге́