Should she date her ex-boyfriend’s brother?

Should she date her ex-boyfriend’s brother?

“I dated a guy for 9 months and met his family two months in, including his older brother. There was some chemistry and it wasn’t until a month ago that I found out he thought the same.
I broke up with my ex a week later. I’d like to pursue things with his older brother, but I don’t know how long I should wait or if that’s even practical since they’re family.”