Sounds like this "mate" is trying to court your husband and husband loves the attention. I don't mean actually date, but you know what I mean? He's trying to impress your husband and he's all for it.
If it were me, I'd take it up where I have the right to - with the husband. He's a grown man, and he's off with this guy, encouraging his disrespectful behaviour in your home and towards you by not saying anything. I'd be past the point of being civil or understanding, your husband is saying this guy needs a break because he has no wife. Not your problem. Let your husband know that his actual problem right now is how this makes you feel.
I've had to deal with friends of DH's that I didn't agree with before, and there's a difference between a guy that you just don't like and a guy that actively changes your DH's behaviour and treats you in a manner that is disgusting. So my advice would be to let your husband know if he wants to be an irresponsible boy again and disappear on your family and not answer his phone - go for it. But don't expect home to be cosy and loving when you return. A grown man with responsibilities needs to act like it, stand up for himself and his family.
I apologise if its harsh, but really, if he hasn't listened to your concerns before then maybe you need to be a bit more stern?