OleOneEye, please consider the likely possibility that your co-worker knows exactly what he’s doing to you - that he is intentionally taking advantage of your empathy and sympathy to get what he wants without working for it.
You described him as “He’s manipulative and passive-aggressive. He’s a whiny, self-pitying man-bitch.” He needs to fix his problems. It is not your job to fix everything, let alone him. If he’s older than you, and working, he must have found ways to compensate for his lack of schooling long before you were on the scene. Let him go back to taking care of himself. You can focus on taking care of yourself, and getting some joy back in your life.
He has pushed you before management for his problems - and therefore threatened your employment - without your full consent. In other words, he’s stabbed you in the back at work. He is making you feel bad on purpose. He has gotten in your head, in a bad way.
Focus on these things when you feel sorry for him.
I had to fire someone who had a bad family situation. I felt terrible! How could I fire someone who was sole support for unemployed husband, and kids - including a profoundly handicapped kid? Then a friend pointed out that I fired her for cause, after many mistakes on her part and many corrections to her from me. My friend said “How could she put her own employment in danger by doing so many bad things, given the precarious situation of her own family?” That made me feel better.
I advise you to find a way to disengage from this co-worker. Be polite, but no more. See how his own choices have contributed to his situation.
Also, IME friends are happy for you even if you have it better than them. A friend of mine has a boat - I could never afford one but good for them! A dear friend of mine barely has two nickles to rub together, but she was happy for me when I bought a house, sent my kid to college, etc. Someone who takes your good news and turns it back on you into guilt is not your friend.
I hope this helps you.