I really understand you want what's best for your family, and as a product of this kind of dynamic (though admittedly with abuse and violence thrown in), I am imploring you both to stop bloody escalating it as my parents always bloody did.
You had a tiff about homework with your 12 year old. So far, so irritatingly normal. He did his homework. Two days later your husband is still stropping over it as if he were the adolescent. Not because homework has not been done (it has) but because he is sulking because he feels the incident is all about DISRESPECTING MAH AUTHORITAAAAY (cue Cartman gif) and you're hand wringing and crying out your heartache.
I'm sure this is not an isolated incident and that your son can be a right royal pain in the arse, but Christ your home will be almost as exhausting as mine was if every minor spat drags on for days like this and becomes all about your husband's feelings. I've been that 12 year old. It is bloody draining. Parents need to set an example and not expect 12 year olds to have the emotional maturity of 22 year olds.
As for the swearing from your son, that's a separate matter. But before deciding what to do about it, check to see where he picked it up. Again, my father resolved all issues by screaming, shouting, swearing and being violent, yet my parents could never work out why my siblings and I did the same in our squabbles. I'm not saying you and your husband do this, just asking you to look for the source.
As for his simian posture, that's teenage boys. It's great not to be a teenage girl any more, isn't it?