Ese voluntario es solidario y siempre ofrece ayuda a quien la necesita.

Ese means that and points to a specific person who is a little removed from the speaker, either physically or mentally.

So:

• este voluntario = this volunteer
• ese voluntario = that volunteer
• el voluntario = the volunteer

Using ese suggests the speaker is identifying a particular volunteer: that volunteer.

In Spain Spanish, the difference between este, ese, and aquel is often taught as:

• este = near me
• ese = near you / not near me
• aquel = over there, farther away

In real life, ese is very common for that.

Here, voluntario is a noun and means volunteer.

In Spanish, many words can be both a noun and an adjective:

• un voluntario = a volunteer
• trabajo voluntario = voluntary work

In the sentence Ese voluntario..., it is clearly a noun because it refers to a person.

Spanish uses ser for essential qualities, identity, and more permanent characteristics, and estar for states or conditions.

Here, solidario describes the volunteer’s character or usual nature, so ser is the natural choice:

• es solidario = he is a supportive / compassionate / community-minded person

If you said está solidario, it would sound unusual, as if solidarity were just a temporary state in that moment.

Solidario usually means something like:

• supportive
• compassionate
• in solidarity with others
• willing to help people

It is not always a perfect one-word match with English solidary, which is rare in everyday English. In this sentence, solidario suggests someone who cares about others and acts to help them.

Ofrece comes from the verb ofrecer, meaning to offer.

This verb is irregular in the present tense because the e in the stem changes to ie in most forms:

• yo ofrezco
• tú ofreces
• él/ella/usted ofrece
• nosotros ofrecemos
• vosotros ofrecéis
• ellos/ellas/ustedes ofrecen

So ofrece means he/she offers.

Be careful not to confuse:

• ofrecer = to offer
• la oferta = the offer / deal / special promotion

In Spanish, abstract or general nouns often appear without an article when talking about them in a general sense.

So:

• ofrece ayuda = offers help

This sounds natural because it means he offers help in general, not one specific instance of help.

Compare:

• ofrece ayuda = he offers help
• ofrece una ayuda = he offers a particular help / one form of assistance
• ofrece la ayuda = he offers the specific help already mentioned

In this sentence, the general idea is best: he always offers help.

Here, a quien means to whoever, to the person who, or to anyone who, depending on how naturally you translate it.

So:

• ofrece ayuda a quien la necesita
  = he offers help to whoever needs it = he offers help to anyone who needs it

The a is there because the verb is offering help to someone.

Both quien and que can refer to people, but they are used differently.

In this sentence, quien is very natural because it means something like whoever the person is who... or the person who...

• a quien la necesita = to the person who needs it / to whoever needs it

You may also see structures like:

• a la persona que la necesita
• al que la necesita
• a quien la necesita

Here, a quien is elegant, concise, and very common in writing and careful speech.

Because here quien is a relative pronoun, not a question word.

Compare:

• quien = who / whoever / the person who
• quién = who?

Examples:

• Ayuda a quien la necesita. = He helps whoever needs it.
• ¿Quién la necesita? = Who needs it?

In Spanish, interrogative and exclamatory words usually take an accent:

• qué, quién, cuál, cuándo, dónde, cómo

But relative uses usually do not.

La refers back to ayuda.

Why la?

Because ayuda is a feminine singular noun, so the direct object pronoun that replaces it is also feminine singular:

• ayuda → la

So:

• quien la necesita = who needs it
• literally: who needs the help

This is very common in Spanish: once the noun has been mentioned, a pronoun is used to avoid repetition.

Because it agrees with quien, which is treated as singular here.

So:

• quien la necesita = whoever needs it / the person who needs it

Even though in English whoever needs it can feel broad or plural in meaning, Spanish commonly uses singular grammar with quien.

You could also find plural forms in other structures, but in this sentence the singular is completely normal and expected.

Siempre means always, and its position here is very natural:

• siempre ofrece ayuda

In Spanish, adverbs like siempre, nunca, a menudo, and ya often go before the conjugated verb.

Other positions are sometimes possible for emphasis, but this is the most straightforward and neutral order.

Compare:

• Siempre ofrece ayuda. = neutral and natural
• Ofrece siempre ayuda. = possible, but less neutral in many contexts

Yes, that is possible in many contexts, but the tone is a little different.

Compare:

• a quien la necesita = more concise, smooth, and slightly more formal/written
• al que la necesita = also correct, a bit more explicit

Both can mean roughly to whoever needs it or to the one who needs it.

The version with a quien sounds especially natural when referring to people in a general way.