Он часто обращается к соседу за помощью.

Yes, обращается is the reflexive form of the verb обращаться.

In Russian, -ся / -сь often marks a reflexive verb, but that does not always mean the action is literally done to oneself. Very often, it is just part of the verb’s standard form and meaning.

Here:

• обращать = to direct, to turn, to address something
• обращаться = to turn to someone, to appeal to someone, to ask someone

So in this sentence, обращается means something like turns to or goes to someone for help.

It is best to learn обращаться as a whole verb.

Обращается is:

• present tense
• 3rd person singular
• from the imperfective verb обращаться

Because the subject is он (he), the verb must be обращается.

A few forms:

• я обращаюсь = I turn/apply
• ты обращаешься = you turn/apply
• он/она обращается = he/she turns/applies
• мы обращаемся = we turn/apply
• вы обращаетесь = you turn/apply
• они обращаются = they turn/apply

In Russian, the present tense of an imperfective verb is commonly used for repeated, regular, or habitual actions.

So:

• Он часто обращается к соседу за помощью.

means He often turns to his neighbor for help or more naturally He often asks his neighbor for help.

The word часто (often) makes the habitual meaning clear.

Because the verb обращаться often takes the pattern:

• обращаться к кому? = to turn to whom?

The preposition к requires the dative case.

So:

• сосед = neighbor
• к соседу = to the neighbor

This is why you get соседу, not сосед, соседа, or соседом.

That is the dative singular form.

For many masculine nouns ending in a consonant, the dative singular ends in -у or -ю.

So:

• сосед → соседу

Because the preposition к requires the dative, you must say:

• к соседу = to the neighbor

За помощью means something like for help.

A very common Russian pattern is:

• обращаться за чем? = to turn to someone for something
• идти за чем? = to go for something
• послать за кем/чем? = to send for someone/something

So the sentence has two parts:

• к соседу = to the neighbor
• за помощью = for help

Together:

• обращаться к соседу за помощью = to turn to the neighbor for help

Because after за in this meaning, Russian uses the instrumental case.

So:

• помощь = help
• за помощью = for help

This is a pattern you should memorize:

• за + instrumental can mean for in the sense of to get / to seek / in search of

Examples:

• идти за врачом = to go get the doctor
• обратиться за советом = to ask for advice
• прийти за документами = to come for the documents

They do different jobs.

• к соседу tells you to whom he turns
• за помощью tells you for what he turns to him

So the structure is:

• обращаться к кому? за чем?
• to turn to whom for what

In this sentence:

• к соседу = to the neighbor
• за помощью = for help

Yes, that would also be grammatical, but it is a different structure.

Compare:

• Он часто обращается к соседу за помощью. = He often turns to his neighbor for help.

• Он часто просит соседа о помощи. = He often asks his neighbor for help.

These are close in meaning, but обращаться к кому-то за помощью can sound a bit broader or less direct than просить. It can suggest seeking help from someone, not just the act of asking.

This is the imperfective / perfective pair:

• обращаться = imperfective
• обратиться = perfective

Use обращаться for:

• repeated actions
• habitual actions
• ongoing process

Use обратиться for:

• a single completed action
• one occasion of turning to someone

So here, because the sentence says часто (often), Russian uses the imperfective:

• Он часто обращается...

If you wanted one completed event:

• Он обратился к соседу за помощью. = He turned to his neighbor for help / He asked his neighbor for help.

No, Russian word order is fairly flexible, though some orders sound more neutral than others.

The given sentence:

• Он часто обращается к соседу за помощью.

is a natural, neutral order.

You could rearrange parts for emphasis, for example:

• За помощью он часто обращается к соседу. = It is to the neighbor that he often turns for help.

But for learners, the original order is the safest and most natural to use.

The main stresses are:

• Он чáсто обращáется к сосéду за пóмощью.

Word by word:

• чáсто
• обращáется
• сосéду
• пóмощью

Stress matters a lot in Russian, so it is good to learn words with stress whenever possible.

Not always, but very often when it means to turn to someone / address someone / appeal to someone, it uses:

• обращаться к кому?

Examples:

• обращаться к врачу = to go to a doctor
• обращаться к друзьям = to turn to friends
• обращаться к читателю = to address the reader

In this sentence, that is exactly the meaning, so к соседу is the correct pattern.

A useful way is to break it into chunks:

• Он часто = he often
• обращается к соседу = turns to the neighbor
• за помощью = for help

So the core pattern is:

• обращаться к кому-то за чем-то

If you memorize that pattern, you can make many similar sentences:

• Она обратилась к врачу за советом.
• Мы обращаемся к друзьям за поддержкой.
• Они часто обращаются к нему за помощью.

That pattern is more important than translating each word separately.