There's this stray cat who has decided to adopt us as its food providers. I don't mind putting food and water out for him at all but now that it's starting to get cold, I'm getting worried about him having proper shelter and keeping warm, especially since he's scrawny as hell and doesn't have the extra protection from any fat.

What makes for a proper kitty shelter? I was thinking of getting a smaller sized cardboard box and lining it with fleece along with making a little nest/bed on the bottom of it.

Pic related, it's him in his current 'home.' ;_;