Dear rosepetals,
First of all welcome to the SR family, I am so glad your are here, but so sorry for your situation.
Please repeat after me, It's not my fault, I did not cause it, I cannot fix it!
His drinking is his issue, all you can control is your reaction to it.
Do you attend al-anon, there are on-line meetings if it is hard for you to get out.
Consider getting a small safe for your medicines, the prices have gone way down, they are now very affordable
He either does not think that mixing medications and alcohol is dangerous or he does not care, either way it could have deadly consequences.
He is stealing your medication, that could put both of you in real danger.
I hope you will get some counseling, and consider all your options, if you need to vent or need a shoulder or a hug I will be here.
Best of luck,
Bill