I have a 11 year old girl, we think the hard part part of having kids is to change diapers and wake up every 3 hours to feed, ha! We were so wrong.
I have a 2 years old baby and I found her a lot more easy to talk with.
I think is kind of normal these changes but is not ok for let it happen, if for some reazon your husband is allowing him to do it you should not. Not as much for your husband but for the good of your son.
It is really hard for me to give you an advice because I don't know the relation ship between your husband and your son. It is possible that your husband drinking and the stress at the house is stressing your son as well? Maybe he looks wrong that your husband drinks and he is dissapoint?
My husband is very cold with my 11 years old, he doesn't want to deal with the drama which it piss me off, I often have to be like the coach in my family (which is so tiring job).
I sadly have come to the conclucion that even some good changes have been made, my husband is an adult and is hard to change at that point unless they recognize they are making a mistake and want to fix it.
However I can tell you what it looks that have be work a little with me and my daughter.
I use to be a very strict parent, I was educate old style, with spanking and punishments, so that is what I did, I learn that be afraid is not the same to respect.
I now never hit my daughter, always, always tell her I love her, and I do very often, I sometimes hug her even when se get enoyed but I explain that even if its enoying, I know deep inside she will appreciate...one day.
This doesn't mean that now I let her walk over me, I still ponish her for what she does wrong and I make sure she finish her punishment but I talk more with her, in fact that is one of my punishments, lol.
I said, baby I will not scream not yell and totally not hit, but we (most me) are going to talk and talk and talk and talk and talk. I have the feeling she just get 10% of what I said on those moements but 10% is better than none.
We are talking more now, I try keep the communication rolling even if most of the times is me the one that talks, and I found that sometimes make her laught is as bigger bond then talk, so when I pick her up and turn of the radio and "sing" Lady Gaga as loud as I can!
So I guess my advice is to not let him act wrong, be firm on what is expect but do it with respect and calm... and keep him laughing.