To be frank, if a student is going to be unhappy , they'll be unhappy : I am not sure the university makes a huge difference. For some, being away from home for the fist time, without the same support mechanisms they had at school, and at home, is overwhelming and not something you truly know how you will react to until you get there.
York has in its favour that it is quite small and has small units within it (although that can also be rather claustrophobic). I did have two friends drop out : one was failing. and one was homesick.
Bristol is the uni I can name that has had big problems recently with suicides and has been called to account for its provision for struggling students.
There is a drinking culture at all universities. But, unless it has changed a huge deal, York never really had that huge freshers' week, student union thing going on. I was never put under pressure to drink but uni is where I 'discovered' drinking as a social thing (prior to that I lived in a 'dry' district of Glasgow!) : your DD could change quite a lot.
I went to an Open Day at half term and the guy talking said between the ages of 18- 21 people change more than at any other point in their lives : and I think that is true, very true.
In summary, though, York is a safe city, very friendly, just the right size, and down to earth, lots of students but also a good relationship between town and gown. There are lots of job opportunities for students, too. I had my ups and downs there but wouldn't swap it for anywhere else I could have gone (apart from maybe Oxford!)