Is it over?

I js think it's because of the genes of my grandpa cause he was about 185 before getting and old and now at 60 something he's 180
Might be alright, ask your brother or just try to follow what he did, ask him and your grandpa when their last growth spurts were. If you want to try and force one you can use hgh, but fasted cardio and training legs more often will probably help