So my girlfriend and I live in a thousand square foot apartment, and this morning my brother called asking to stay with us for a week. I told him I'd have to get back to him after talking to the gf.

My gf and I are 23 and 22. My brother is 32.

Recently he was kicked out of his house by his girlfriend and has nowhere to stay. My mom said he could stay with her, but she's out of town until at least the 21st. He'd be staying with us for six days.

I'm seriously torn here.

There are some pros and definitely some cons to letting him stay with us.

Pros:

* Although we're not very close, he's still my brother and it's probably the "right" thing to do.
* None of the guilt that comes with telling him no. I'm sure my dad would understand if I said no, but my mom is a notorious guilt-tripper and my brother seems to have picked some of it up as well. I'm not very close with any of them, but it would still hurt a bit to know they're mad at me.

Cons:

* We don't really have a lot of space. We have a bedroom he could use, but my gf keeps all of her clothes in there. She's not a big people person, so making her walk around him sleeping at 6:30am for her clothes every morning for six days is a huge ask.
* I'm worried about the strain it'll put on my relationship with my gf. As I said, she's not big on people. Especially people she doesn't know that well staying in her home for extended periods. It doesn't feel right to subject both her and I to the kind of stress it'll cause.
* My brother has a history of drug use, and while he has been clean for more than a year now, it's still hard to trust him completely to be alone in my apartment for so long. Some past experience with a different brother makes me even more anxious about this.
* This last one is kind of petty, but we had plans to have some out of town friends come down this weekend and most likely spend the night. And I really don't want him here when they come down.

I'm leaning toward telling him no, but I still need to talk to the gf about it all. But if I do tell him no, I don't know what other options he has. I know he has a decent job, and I think he might have a bit of money, so maybe he could stay in a motel or something? 

I don't know. 

Help me Reddit. Am i the asshole? Should I help a family member who is down on their luck? Or should I do what causes the least amount of stress in my own life?