I got into a fight with my brother. I'm 25 and he's

I got into a fight with my brother. I'm 25 and he's 23. We're living together. He wanted me to read his cover letter for a resume he is going to submit. It wasn't due right then and there and I had an appointment that I was going to be late to. He badgered me into reading it before I left and I relented. I go to read and he's there proofreading it so I say, "Come on, let's go, let me read it," and he freaks out and says, "Dont bother if you're going to be like this" and didn't let me read it. This came a day after we got into it for something that was my fault and that I apologized for. I feel like he's holding it over my head and that generally he tends to be manipulative if I tell him no, he gets upset. He literally left the apartment and he went back to our parents house and acted like I killed a puppy. My mom is taking his side and I'm pretty sure this is the "last straw" with me far as they're concerned.

Is this manipulative behavior? Is there any chance he'll cool off? Is there anyway to get them to generally respect my boundaries and respect me more in general? I know this is some childish shit but, like, it's fucking my life up and it's part of a trend of behavior on their part where everything turns into a power struggle. I feel like they arent willing to compromise with me on any level.

Am I in the wrong or are they?