Was he flirting or just being nice?

Ok. So I know this guy, robert, and by the way he talks, and some things he says, me and my friends suspect he might be gay and hasn't "come out" yet. I was at my friend's birthday birthday about two week ago, and he was there. We were all sittin outside (waiting to roast marshmellows) and it was freezing. He turned around and asked if we were cold. I said yes, and he offered me his sweatshirt. I said "no, i'm ok". but he kept offering and staring at me, until finally i said "i promise i'll tell you if i want it" and then he patted my knee very softly. it seemed like he really wanted to give me his sweatshirt..was he flirting with me?