Just need to get things off my chest

I been with my bf for 3 years almost 4 and he has a brother and him and his gf have been dating for 5 years. And sometimes it seems like his parents like the brothers gf more. No im not jealous at all i love his bro gf she's so nice and sweet. But his parents are always giving them sweet compliments and always comments sweet things on her fb post. Like recently the brothers gf posted a pic of them and my bf dad comments i can't wait to have u as our daughter and that he can't wait until my bf mom spoil her. That kinda hurt my heart i a little cause i sweet comments like that. And i know his family loves me stuff but seeing that comments hurted me alot. And idc at all if his mom gets me anyting cause she doesn't have to. I'm just scared that when me and my bf are engaged and married that i won't get treated like i should. His grandparents treat me wonderful and are always giving us sweet compliments. But his parents not so often. Im sorry if im over all the place but im just a little hurt by it. Please don't judge. I just wanted to get it out of my chest and again im not jealous of her. (Btw me and my bf always told each other and we can tell that his brother and gf are his parents favorite you can easily tell.)