I agree with HeChoseDrugs. ask yourself if it's healthy for you?
I also just don't think it will help him regardless. My mom has been great with reminding me recently that people abusing drugs don't care about us at all while they are doing it. We wring our hands about how they will feel if we don't show them how much we love them. Meanwhile they don't, can't care at all.
You can give him money but that won't stop him from selling drugs anyway. So there is no point. And he will use your money for drugs. You don't want that on your head.
It's so hard to truly accept that you cannot control their actions, and that nothing you will do is going to change what they do. Meetings are really helpful with this.