Hello. Ok, you have asked for honest answers so I will be straight forward with you. I think you are putting a lot of pressure into an already pressurised situation. Try and step back a minute and look at what you have written.

Realistically he is very unlikely to be able to stop drinking before he gets the chance to immigrate. The whole experience will be of heightened stress so its not a great time to be trying to stop. PTSD sufferers obvioulsy do not deal well with stress so at these times may self medicate more.

I can see you are stuck with this but I think all you can do is encourage him to cut down and therefore save more money. If he doesn't have enough to immigrate this time is there a possiblitity to postpone it until he does?

Ultimately it is down to him. I assume he knows the deal. Its in his hands. You can encourage but that is all.