I met a guy on another forum a while ago. He revealed that, after a couple of suicide attempts in the past, he is going to kill himself sometime after July. Because I only know him from online, I don't live close enough to actually get him to a doctor or call the cops.

He has an abundance of mental and physical health issues (schizophrenia, psychosis, a heart condition, depression, etc... the list goes on) that he can no longer tolerate. He's felt suicidal for a long time because of all these issues, and has attempted suicide even while on his meds. It's difficult for him to address his problems because his severe depression and psychotic episodes distort his rationale; he doesn't know what's right and wrong, or if what he "sees" is real or a hallucination. He sees a therapist, has a good family and one fairly good friend in real life, but it's not enough for him to want to keep on living. Everyone says that "life gets better", but it hasn't for him. There isn't a single day where he's not thinking about wanting to kill himself.

My question is, what can I do to help him and make sure he doesn't kill himself in two months? I rarely talk about my own problems and neither do my friends in real life, so I often don't know what to say when he opens up about his problems... If anyone has advice or uplifting words to give him that is actually helpful and empathetic, I would greatly appreciate it.

Why it must be July? Have you ask your friend that? I think you will find a clue from it

There is someone who he feels indebted to, so he is going to wait until after he has repaid this "debt", which would be in two months.

So he going to pay his debt, but why it must be two month

I think the best way to help him would be to meet him face to face. To show him there is someone who cares about him and wants him alive. Ask him to meet, if he's planning suicide, he shouldn't be afraid to meet someone on the internet, and by meeting in a public place like a restaurant, you prevent him from hurting you if he's not who he says he is. Talk to him about your life, and ask him about his. Give him a reason to keep living.

Yeah meet him in person and tell him that you care for him and ask why he wants to die, and can I have a few words with that friend of yours (if he feels happy to talk to me)