Why would my boss target me?

He is a 54 year old guy who is single and takes care of a sick relative and said he has no other family. He was married or so for 13 years but no more abd his ex found someone else. Always approaches me and talks and constantly teases me about things I like. Sometimes he sings to me. Other times he acts annoyed with men I talk to.

The other day I asked this vendor about having any alcohol samples and my boss came nearby and said he won't allow me to have any alcohol around him, how alcohol is not good for me. I told him he won't tell me what to do, like what, is he my dad? He got pissed at calling him dad and said he is not that. OK I said, are you my husband to tell me what to do? And he said not today.

Is that all flirting or just trying to be nice?