Search Results: flirt after break up

There’s a backstory to this question.

My younger cousin who is a senior had a bit of drama today involving her on-and-off boyfriend (?), Nathan. Both are 18. They broke up at least 4 times over petty things and dated people in between their breaks. Anyway, Nathan dated this girl who was a sophomore (Patty) and they broke up for whatever reason so he went back to my cousin while Patty dated someone else. However, he would still flirt and being intimate with Patty and my cousin found out when Patty “confronted” her after she logged onto his messenger and read the conversation he had with my cousin. She was furious and broke down to her friends in tears. One of them in particular kind told her they told her so and informed her that the Patty was crying as she found out her boyfriend had cancer and my cousin said she didn’t give a fuck, which lead to her friends calling her fucked up for saying that and left it at, “I don’t care.”

She told me this at home and said she kind of felt wrong for saying she didn’t care about someone having cancer but at the same time said she thinks the girl is lying for attention (which she allegedly famous for), didn’t know him and had no connection to him so she didn’t understand why she SHOULD have to care. I didn’t know what to say. Obviously, she said it out of anger and frustration but do you think it’s wrong to not care about someone else’s misfortune or at least not be sympathetic towards it in general.

One of my male coworkers and I had genuine feelings for each other but we never made any move because he had a girlfriend. I always kept distance out of respect for that girl. We admitted our feelings earlier this year but he gave me very confusing answer implying its difficult as he and his girlfriend have talked about marriage. I stepped back and avoided him. he realized he has hurt me. after 2-3 months, i noticed what seemed like he was texting on a dating app. I stayed quiet and away. i could tell he had started seeing another woman. In last 3-4 months, he started showing interest in me again. i didn't act as i thought he has a girlfriend.
recently, i got to know that he has bought his own apartment and his girlfriend has not moved in with him. also, he has asked two of my female coworkers if they know rich single woman. clearly he is single again but at work he has not openly come out as that. if i avoid him, he gets very interested in me and flirts with me. yesterday i gave him a box of chocolates for Christmas. he was very happy but after sometime, i heard him loudly mention his girlfriend to another female coworker. it seemed like he was wanting me to hear that (he has done this before too) - sort of pinching me and trying to give the false impression that he is still with her.
i felt so hurt. i really feel like telling him that i know what he is upto recently (he single again, seeing another woman and looking to get introduced to rich single women) and wish him good luck. should i do that or just stay quiet? lastly, i know from his behaviour that he still has feelings for me but is not pursuing me.