My cat is suddenly getting cuddly

I'll give you as brief a background as possible (sorry) if that's helpful.

So, I have a question. I have a five-year-old cat; I got him in my early twenties. We've always been with the two of us. The family he was born into was always very distant towards him and his siblings. Since I got him, he would sometimes lie next to me or halfway on my lap at first, but that quickly changed. He prefers to be close to me, but at a distance without any touching, and I completely accept that. I don't push him, and every cat shows affection differently. I can always pet him, but if it takes too long, he prefers to brush me off and do his own thing. He's also an indoor/outdoor cat and loves being outside and hunting. But last week, I started sitting on the couch and he would come and lie on my lap. I was very surprised because this had never happened before. And it now happens every time when I sit on the couch!! :) When I go to bed, he now also likes to lie next to me, near my head and shoulders; he wants to be wherever I am. I love it, of course, and hope it makes him happy. But I'm wondering how this could happen so suddenly. I sometimes read that when cats are nearing death, they seek more attention and prefer to stay close to you, but I really hope that's not the case. He's been suffering from bladder stones for the past two years, but he's much better now (confirmed by the vet) Maybe this has something to do with it, or maybe not. I thought I'd share this to see if anyone else has experienced this or knows what caused it. Sorry for the long post.

(English is not my first language so sorry if there’s anything not understandable)