I really think you made the right decision, and it must have taken a lot of courage. My Uncle was an alcoholic, but my Grandparents enabled him to keep going by paying his rent and giving him money. The story did not end well - he went missing after a binge and his body was found a month later. If he hadn't been able to rely on that stream of income, he might still be with us.
The best thing you can do for him right now is keep in contact and hold your bottom line. You might consider going to a counselor to learn how to communicate your concern without setting off his defense mechanisms. It might help with your anxiety too. I wish you the very best of luck.