My boyfriends creepy uncle.

Last night, I went to a family reuinion with my boyfriend. It was considered the "small one" even though there was a ton of people, but the big one with everyone there is today and I'm going to that one with him too. Anyways, last night, I swear I saw his uncle checking me out more than once. My boyfriend and I got there early, and as soon as his uncle walked in I got creeper vibes from him. and I caught him literally looking right at my boobs the last time before we left. I was wearing a v-neck, but you couldn't even see the crease between my boobs. granted, I'm kinda short and he's very tall so he might've been able to see something. I finally told my boyfriend what was going on and we left immediately after. I'm kinda nervous about going today, his uncle is somewhere between 50 & 60 and I just feel completely weirded out by it. What do I do today if he does it more or takes it even farther?