I've done this a few times through my life, especially lately as I've finally been getting my own life stabilized. Here's some more "notable" examples.

A family member, where I've been trying to mentor them and help them in every way I possibly can - sometimes at great personal cost - but as the saying goes, I've led them to water but I can't make them drink. Still won't give up, though.

Another family member I've done the same for has actually been trying to take me up on it. Still early stages, but they've started on applying for college in a field they're interested in. I'm helping them study since it happens to be adjacent to my own field, and I'll help cover the bulk of the cost if they don't qualify for gov't funding. I'm really hoping things work out for them.

The only time I've really actually seen obvious results is in my students where I volunteer teaching English. One student in particular really struggled to read even a single word, but in less than a year, they can now read most sentences on their own - which is honestly just insane to me.
Obviously it's like 99.999% their effort rather than mine, but I like to think I'm helping lol.

...writing this all out makes me feel like I'm bragging or something. Really I've just been in a rough spot for most of my life, and now that I'm getting my life together I'm just trying to give back a bit where I can. I just want everyone to be happy, lol.