My(20F) father passed away unexpectedly from a sudden cardiac arrest a few weeks ago. One of my friends (21F) has been talking about this guy (Let's call him "D") for a few days even before my father's passing but due to his background, behaviour etc the guy wasn't accepted much within our friend group. But she had gone on a date with him without telling any of us. Here's where it gets me involved and honestly it got me pretty upset. Apparently she's not felt a spark with D, and has decided to lie to him using my father's passing, the lie being that "when she was talking about him with one of our other friends during my father's memorial ceremony (a memorial ceremony is held week after a death in our culture) someone else there who also happened to know about D's past had overheard her speaking about D and had told her to not be associated with him anymore" and she has made him believe that it was the reason of her breaking things up with him. She had told this lie without even discussing with me beforehand and called me right after asking to "save her" because he won't "leave her alone". So when D questioned me about it I just pretended to not say much and honestly not know the person that told her about his past because there's genuinely no such person and it was all a lie she made up. First hearing how she used my father's death as a cover up actually got me pretty upset which I did mention but she never once apologised for. Then comes last week, which is probably a month after that whole incident. She has found her self a new boyfriend that being one of D's classmates and flaunts the relationship in anyone's face, that including D's. I think D has grown resentful from her breaking things with him and replacing him with a classmate of his just within 2-3 weeks. So he cornered me and started questioning me about the guy who told her to leave D. Sort of threatening me and saying he won't let it go that easily and how I must know who the guy must be and just protecting him etc etc. So I told D that I knew no such thing and to leave me alone. Which D just scoffed at. Honestly I'm super annoyed and upset about having to deal with all of this while I'm still mourning my father's death, and having one of the friends I trusted make up lies based on my father's death and using such an event as a cover up all because she couldn't directly tell him that she's not into him. So AITAH?