am i overreactibg? (tw for suspicions of sa?)

My childhood friend’s brother always been there, he’s transformed into a jerk who bullies his sister onto the verge of tears. I don’t like him, yet I have trouble setting boundaries. Often times he drags me away from talking to his sister, sometimes pulling me away or choking me. Well, not genuinely choking me, I guess in a playful matter, but he generally uses physical force to get me to do something. I didn’t really mind it since it was just banter between the two, their roughhousing wasn’t inherently malicious. But I’ve been growing really uncomfortable ever since that trip started.

Tickling’s a new method, and I didn’t mind that either. There are some times where they don’t listen when I asked them to cease. But I never fully reiterated my genuine commands to stop to them, it was only when I was laughing about it. I guess you can’t exactly blame them if I don’t sound serious. And they were short, so I didn’t care. However, lately her brother seems to show me more suggestive/sexual content on my phone for shock value. He’s been dragging me away from talking to his sister a lot more now, making fun of her and berating her when I’m there. He’s starting to drag the tickling into longer sessions until I’m like, on the floor, I guess. He’s also getting bolder and started touching my thigh a lot, I make sure to slap his hand away.

I think what really startled me was the time where he and his sister entered the hotel room while our parents were out eating, and for some reason his sister left the room. Without context and before I could really call out for her he started tickling me again- like this time he wouldn’t stop. At one point he genuinely pinned me to the bed but stopped when the door started unlocking. We acted casual after but I don’t really know what to do or how I could even ask for more clarity on the situation. I can’t say that he’s being inherently malicious, and I’m really embarrassed that I can’t talk to someone who is a year younger than me—stronger than me,  as well

Sorry if I’m being explicit about the matter. I don’t want something to happen to me, or at least, I don’t want to exaggerate plausibly innocent situations.