I don't think there's anything wrong with him going out and having a skinful once every month or two.
However, his behaviour when coming home - ringing you, waking you up, buzzing the intercom, waking the baby, ringing your mum (!!), etc is totally unacceptable.
So have a chat with him (when sober). Tell him he is welcome to go out, but he needs to make his own arrangements regarding getting home/staying in a hotel, and he is not to ring or wake you or anyone else in your family. Your phone will be switched off from 10pm, and he's not to contact you from that point onwards.
And if he doesn't get in touch til 5pm the next day, then so be it.
It's only once every month or two.
And I suspect he does know in advance that he's going for a "big" night out, but is too scared to tell you.
He sounds like a rebellious teenager, and you sound like his overprotective mum - its hard to know which is the cause and which is the effect, but you need to break the cycle.