Moving to Scotland w/ no job? Residency questions. (Glasgow)

Hi - I'm in what's maybe an unusual situation. My father was born and raised in Scotland, but emigrated to the US in the '50s. We are considering moving to Scotland and buying a house, but are worried about what services we would and would NOT be able to use. In particular, would my dad be able to live, say, in Bield housing (it's a housing scheme for older people) ... would we be able to use the NHS ... etc etc. I know as tourists we're covered, but if we lived there it might be different. My dad seems to think it'll be no problem, at least for him as a former British citizen, but I'm not so sure. If we could get HIM in, then I could probably come as his caregiver as he is 88 years old.

We have relatives in Scotland; has anyone been able to secure residency through their relatives? I really just don't know how it works. I know I wouldn't be able to work and take a job from a UK citizen; what about working for myself, making and selling crafts? If anyone has any experience, or any links they could pass on that would help me out, I'd appreciate it. I'm not interested in doing anything illegal; I want to know what I'm allowed to do legally! Thanks so much.