Edit: My news can wait for something like this.
Gryff, he sounds like he's treating you like a kid that needs to be watched. That is, of course, the surface of the matter. I would seriously consider why he's doing this, your history, and definitely ask for an explanation. The key to that explanation is you need to put any hurt feelings and emotions aside. He might have a good reason for it. Maybe his sister is... well, not-so-awesome and he wants to protect you from that. It might be that he's embarrassed of her for whatever reason. She could be a member of the Westboro Baptist Church. o.o
And if it turns out that he doesn't want YOU to be around, then is that because he just wants quality time with his sister or is it that he doesn't want you around because you'd annoy him? If that's the case, seriously reconsider your relationship. If he wants something like honest, quality time with her to catch-up or if she's treating him to something awesome, and he's just considering her wallet, those are things that, while they suck, they're fair explanations. If he has no real explanation or hints that he doesn't want you there for negative reasons, that's totally different. If he's seeing you as an embarrassment, then I would reconsider your relationship.
I dated a guy who treated me like a kid and HATED that I cosplayed, and while he was sweet to me, I realized once I was out of that relationship what an a-hole he was to me most of the time. He would literally call me a kid and say that he felt like he had to take care of me. That was when we argued though. Which was fairly frequent...
Well, if you're friend gets called in, places like Pioneer Mall are good to hang out in. There's a movie theater that you can waste at least two hours in right there. Art Media is really close to that, too. If you need food, the food carts are awesome and super cheap. You can get a great quality meal for $6.
Gryff, I would offer to hang out with you, but I don't know if you'd be comfortable with that, and I don't know what time this is happening at either. I'm meeting up with my friend then on Saturday. :/ Anyways, I hope things work out in your favor. Hang tough, Gryff.