This is the only time he (M20) has been friendly toward me (F19)

Idk it’s weird ! I was always so eager to be friends with him again because the way things left off were weird but not bad at all. We had a nice time together while it lasted. Now that the new year and new semester has started we don’t talk whatsoever! I would really love to be friends with him again but he always looks upset when I say hi to him. Here’s where the plot thickens! The only time he didn’t look upset at an interaction between us and was super friendly is when I was visibly upset at my BF. Does this mean anything? And should I try to pursue a friendship? ( I haven’t done anything besides say hi to him twice out of the entire year. Just being cautious before I make a decision )
TL;DR

Background info: we had a short fling and it ended because I ghosted him for almost the entire day one time which is my fault and I’m not playing victim , but on his end he cancelled plans twice and I suspected he wasn’t telling the truth so that is why I ghosted him. He was a little pissy at the fact and did give me hard stares on campus afterward, but other than that it’s been pretty neutral between us. No ill will, at least I think so? Idk I don’t think he’s ever talked shit about me but I would hope not ! He has asked about me to one of my friends but that’s all I know.