how do i support someone i cant help?

my girlfriend and i are long distance but i love them more than anything else this world has to offer. on the good side, she is one of the only people who goes out of their own way for me and genuinely makes me happy just by existing. i couldnt imagine being with anyone else after everything we've been through.

i want to give her everything she could ever need, but the one thing they do need right now is something i cant give them. after we graduated, they moved in with a friend and the family is genuinely sent from ***. they laze around all day and treat them like their personal maid and their friend cant do anything without getting into trouble either. its been a constant cycle of people taking things from them and getting nothing in return their whole life, and i can see its finally on that last thread.

they were never given any opprotunity to get a job or their permit as their school was a strict boarding school. they have no experience in the real world because no one was there to give them the opprotunities most people our age got. theyve been constantly let down and i unfortunately did the same to them; i tried to get them down here for christmas and the conversation where i told them it wasnt going to work out was basically a nuclear bomb of pain.

it used to be i could give them advice and be there for them, but now all i can do is sit and listen. nothing theyre going through is something i know how to handle and support, so whenever i see them start to talk about something rough i have to get avoidant for my own sake. its starting to physically affect me and we have no other choice because i am all they have left. ive recommended this app once before so ill have a conversation about it with them again, but i dont know how long thats going to last.

i love them more than anything, and i dont want to leave just because theyre at their lowest. but at the same time knowing i cant do anything to help them out of this is destroying me and slowly tearing me down to the point i almost feel as helpless as they do.

am i supposed to know what to do? how do i put up support when im given more than i can hold?