GUYS i need to know your opinion?

so i was informally dating a guy for a couple of months this summer before he went off to college 4 hrs away, saw him once after he left for school, we had a pretty nasty break-up. he was talking to his ex on facebook & thats who he is now seeing. well several (6 months) after we break-up, his older brother & i are now seeing each other. i know that sounds terrible but the younger brother & i were never that serious, it was more like a summer fling because he did not want any commitment. i really like his older brother, we have fun every time we hang out. we have been having a lot of sex. the first night we made plans to meet up for a few drinks he showed up with 6 or 7 bouqets of flowers so i know that costed him a pretty penny. we have talked to each other every day since that night (we ended up having sex later because i was pretty much intoxicated). we have hung out several times; he is always very sweet. he called me a week later and said "happy 1 week anniversary" which i thought was kind of strange because i didn't know we were like dating i thought it was more along the lines of a friends with benefits thing. he lets me stay as long as i want the next day after stay the night while hes at work, i wrote him a note & he kept it, still has it. he is planning to take me out for valentine's day. i asked him if it bothers him that i slept with his brother & he says the only thing he cares about is knowing that his younger brother is ok with us hanging out, that as a brother he feels obligated to at least ask him and tell him. he says he just doesn't like to think about it. i am really starting to fall for him but i don't want to end up getting rejected or hurt. my question to you guys is do you think he really likes me and has feelings for me? or do you think it's just a hook-up just sex thing? i really hope he likes me and it's more than just sex to him because i really do like him & want to date him. thanks so much for your input.