Do care homes take smokers? One I asked just smiled and said "he will quit."

I'd strike through that one without a second thought, then. Can they even spell "person-centered care"?

More thoughtful facilities will work something out, and those ones are at least making an effort to respect their residents' right to autonomy.

My SO works at a independent and assisted care. They have an outside smoking area for staff and members alike.

I doubt you will find one that he can smoke indoors. That is a thing of the past.

I would ask if they have smoking areas.

My dads board and care home allowed it outside.

Call around and find out. Some do, some don't. But I've yet to see a managed care facility that allows smoking inside the facility or inside a resident's room. Outside only is where some facilities allow smoking. My folks ALF did allow smoking outside in designated areas where they provided those tall ashtray type things for cigarette disposal.