There are plenty on people that are frum on the UWS and plenty that are not. It may not be the frummest place, but if he wanted to be frum there he would be.
I think that the bigger problem is your friend’s family problems. I get the impression that his becoming religious was, to some degree, looking for something to help him. And when that did not materialize, he became disillusioned. I had a friend like that – bad family situation, went to yeshiva. But at a certain point he did not get whatever he was looking for (emotionally or socially or whatever). His turning point was in yeshiva (I saw the apathy coming on), although he was still going with the flow while still there. After a few years he was totally OTD. I would guess your friend is similar.