I just watched Monday's episode, and I am sorry, what the hell? I know that Monica and Brook Lynn are technically family, but she hadn't spent a ton of time with her, and while she does exhibit a few Tracy-like traits (which are really Q traits). Yes, there was that time that Brook Lynn tried to swap $50,000 from Edward, but her own son AJ stole the entire family fortune for a time.
It wasn't just Carly's idea: she funded and bribed Brook Lynn who was in legal and financial trouble.
While Brooklynn was an adult by that time, she was at that weird age where you finally leave the protection of your parents, your early twenites when most are finished with college and starting the next phase. When Lulu pulled what she pulled, it was only 4 years prior (it might have been right before they all turned 18). Georgie married Dillon not only because they believed Dillon was dying from an incurable disease, but because she truly loved him. Early twenty-something adults aren't much more mature than late age teenagers.
I found the entire story problematic not the least because it was negatively impacting a promising legacy character. Also because:
1) Tracy didn't take a more active role. Tracy would have been smart enough to realize Carly was out for blood, and Lulu and Carly being previously close wasn't going to protect Lulu from Carly's vindictive nature. On top of that, Carly was going to use one of Tracy's offsprings (and her only biological grandchild) for petty revenge plans. It doesn't matter that her and Brook Lynn weren't close: Brook Lynn was not only a Q but her direct descendant. Seeing the damage that Carly did to Alan's family, I can't believe that she would stand for it.
2) They never connected Brook Lynn's friendships with Georgie and Uncle Dillon to motivation to breaking up Lulu and Dante. To do that, it would prevent Guza from having the character willingly drug Dante, who apparently was a close friend.
3) I don't believe that Brook Lynn would turn down getting back her trust fund and receiving room and board from Edward in exchange for going back to school (Edward never specified what subject to major in), prefering to work for Carly so she could hurt a friend. Brook Lynn could easily maneuver around her great grandfather stipulations, and if she didn't, could have made good use of a degree in her music career.