Don't leave a piece of jewelry at his house so you can go back and get it later; he may be with his real girlfriend.
My mother always said 'Don't bother other people.' I think that's good advice.
I don't mind pointing out some of the failings of old age, because we are all headed in that direction, unless of course we take our own lives before we become a burden. I'm not advocating suicide, oh wait, I guess I am.
I think it's good for a person to spend time alone. It gives them an opportunity to discover who they are and to figure out why they are always alone.
Accentuaute the positives - medicate the negatives.
Don't answer the door in a wedding dress and veil, he might not think you're joking.