just for dads helping each other

1. The aunt. Is she helping build a healthy environment for your son? If not, she's gotta go my friend. Your son is the important thing. I don't know your circumstances beyond what you've shared here. I don't know if you need the rent money or the handyman stuff, or how bad you need it. There are other tenants, and they've had their whole lives to get their shit together. Prioritize your son, the aunt and her husband can figure their shit out somewhere else if they're not what your son needs right now.
2. Your son. Have you staged a full intervention? Told him how his actions are hurting him and you? Told him he needs help? Told him how bad it's gotten? There's lots of good resources online for staging a real intervention and resources he can engage with afterwards. Intervention needs some for of real ultimatum in it. One of my best friends literally needed his friend group to give him the cold shoulder and refuse contact for months beyond 'are you alive, are you getting treatment yet?' before he fixed his shit. It's tough. It's horrible. It's necessary. He needs serious therapy, a multi-step program, and full cold turkey. Nothing else will suffice.
3. The alcohol. You say your son has no job and no prospects. Where is the alcohol coming from? Where is the money for the alcohol coming from? Does he have keys to a car? Without a job, and considering the alcoholism, why? This is the most obvious vector of attack. The house must be dry, and he shouldn't have access to personal motorized transportation.
4. You. You probably also need therapy, based on the tone and difficult circumstances you've shared here. Don't neglect yourself. In most countries there are programs for help if you need financial aid. Otherwise find a few good friends and find a safe place to vent and feel supported.

In short, I can tell you're feeling hopeless, but don't let that make you an enabler. You need to take agency and do whatever it takes. Your son needs you.