if you’re feeling guilty (which is normal- not deserved, and not useful, but normal) you can also definitely ask them to stop. It can be extra hard to set boundaries in those moments, and if you need a stepping stone or two, you might try something like:
“I know you’re really struggling right now, and I want the best for you. I just don’t have the capacity to be the support you need.” (You can also link them some resources if you like)
When you’re able to, set that boundary!
“I actually feel pretty uncomfortable with this dynamic; I don’t feel equipped to help someone with that kind of emergency, and it’s much harder to say no to that when the person asking is someone I admire/look up to/view as a kind of mentor the way I do you. I understand you probably asked me because you don’t have a lot of options, but maybe you can take some time now, while you’re feeling better, to make a different plan. regardless, I would appreciate if you didn’t ask me for that again, and I will not be able to respond if you do.”
You should be wary of much older people asking you for this kind of support because it’s generally a red flag if someone can only get an emotional need met by people who feel pressured to say yes. even if that person genuinely doesn’t realize the impact they’re having on you, the circumstances themselves are very much a red flag anyway.
The best way to tell if this person is worth sticking around for is how they respond to you setting a boundary. it’s okay to ask clarifying questions or make a conflicting boundary clear so they can respect your boundary in a way that works for you both; but you should always be having a conversation about how they can best respect your boundary. not about what they can get you to compromise on.
and most importantly: they should follow through. mistakes happen, but they should be pretty rare, and grow less frequent with time. you should never feel like your boundaries are being pushed or “tested”. when you remind them, they should never make any emotions they have about it your problem. it doesn’t matter if they’re upset; they can process that somewhere else. you should never be comforting them over hurt they caused you.
you should never feel uncomfortable with an adult. you should never feel like you can’t say no, even if the reason is “I’ll hurt them if I say no”, or “they’ll be sad if I say no”, or even “they don’t have anyone else to go to.” they shouldn’t be making you feel that way in the first place; you should always have room to say no, and even if they might be hurt or alone if you do, they should want you to feel and be safe before they want you to help them.
and I say all of this just because I think it can be hard to hear “just cut them off” when you’re in this kind of situation, and while I agree that you can (and probably should) do that, I know that not everyone feels capable, and might just feel more defensive than anything. I know the kind of guilt that comes from that, and I know the “I’m strong enough for this” justifications as well. these are just some things you can do to protect yourself if that’s not the course of action you feel ready for, and hopefully, even if you feel strong enough, you can use your strength to set appropriate boundaries that can keep that relationship in a healthy and balanced place.