I was talking about this with DH earlier - and my friend not long after. How fucking dare David say 'children make mistakes, and children should be allowed to make mistakes.' As if Brooklyn is a silly naughty little boy, who is just behaving terribly badly at the moment, and when he comes round and realises what a naughty silly boy he's being, he will come back with his tail between his legs. If he begs and pleads enough, we maaaaay forgive him. Bless....' 
As you say OP, he is a 26 year old MAN. I had been in the workplace for 10 years then, I was married, and I had a house, I had a career -
I was an independent adult, who could make my own decisions. I cut off a couple of toxic family members some 32 years ago in my mid to late 20s, (for valid reasons) and was treated like I was some kind of childish fucking idiot, )by a few people.) I had a couple older friends and acquaintances of the family, and a couple of parents neighbours, telling me I was a very silly girl, and I should grow up, and 'you can't just cut off family like this.'
I thought at the time 'just fuck off why dontcha? I am an independent married adult with a mind of my own, a job, a home, and a career. 32-33 years later, these 2 people are still cut out of my life. They never came to my wedding, they have never met my 2 children, and I don't care if they're dead or alive.