There are serious red flags here girl! First off…he was sizing your middle sister up for a relationship before he met you. Guys say crap like that they are just friends but guys are never just friends. Maybe there was nothing from your sister’s side but he was interested in her. Guys don’t waste their time having platonic relationships and especially this one who seems to be on a mission to be married and have a child within the next 12 months.
When a guy is rushing a relationship, there’s a reason and you have to slow down to allow your brain to catch up.
I haven’t read your entire post because I keep stopping by all these red flags.