How to tell my grandfather I don't like his behaviour around me

I am a 15 year old female and my grandpa is a character to say the least. Ever since I was super young he has always been super energetic and the "fun" grandparent. He certainly does not act his age ​and that was a good thing for little me because it was fun to be around and play with him. But now that I am older I can see that he is not who I thought he was​. I obviously now have had social media and I can see the things he posts on Facebook. These things honestly discussed me and it has changed the way I see him. It makes me sad that he isn't the person that I used to know, but that isn't the point. I have noticed his behaviors around my family and especially toward my mom.(He is her father) He undermines her opinions and doesn't listen to her because he thinks he is superior to her I guess. He also makes rude and gross comments. But recently was the first time he has said something to me that has made me uncomfortable​. I knew that he was going to be coming to my house the day he did and I honestly stayed in my room for a while because I was not particularly looking forward to seeing him, but once I came out of my room I decided to go downstairs and sat hi. For context I was wearing a hoodie and sweatpants​. Anyway I go down and give him a hug and quite literally the first thing he said to me was something along the lines of - wow I can believe it you used to be so little and now you've got these boobs and everything.(The way he said it was also very creepy) I was too stunned to speak. I immediately got super uncomfortable and angry and also sad. My mom said something like "oh she doesn't like that" but I just when to the bathroom and started crying because I went in with an open mind and decided that's maybe he would be normal, but no. I could hear from inside of the bathroom my mom talking to him and him asking what he did and how I was overreacting​. He never apologized to me and couldn't see that I was uncomfortable the rest of the time he was here. He is super immature and I see him getting into arguments online and fighting like and sounding like a five year old. I don't know if I should do something because I know he would immediately get defensive and ignore how I f​eel, ​or if I do do something what to do.