It sounds like you have a supportive family who really wants you to get through this. To answer a few of your questions:
Your husband and son should find a local Al-Anon group. (There is a forum on here that discusses similar groups) From what I have been told, these groups are as necessary and helpful as AA is for the recovering alcoholic.
Your son may need additional help, but hopefully Al-Anon will help educate him about alcoholism and give him some additional insight into your situation. Your son may have a better idea of the situation than you think, however he is still only 13 and the additional input from people in similar positions may be invaluable resource.
Best of luck.
-pedagogue