He invited me somewhere with his mother? What does that mean? Why/when would you do that?

Freya
I've been speaking with a guy on campus for the last month or so, and we've been texting a lot. At one point he had confessed that he was interested in me, and while I said that I also liked him, I didn't think I was in a good place to start anything. He respected that, said "maybe someday," and we've been continuing on as friends (with some mildly flirty things occasionally.)
He just invited me to an event that he is going to with his mother. Is that significant? Why/when would you invite a girl (even if she is just a friend) to go somewhere with your mom, effectively "introducing her to the parent"? (Even though it's more like, "I'm going with my mom. You can come, if you're interested.") Would you do this for any girl (I feel like he has a lot of female acquaintances/friends..) Furthermore, I don't think he really has other family. Just his mom. And I'm not sure how close they are, but I still feel like he has a level of concern/protection for her. 
I can be really awkward, so I'm a little afraid that I'm going to do something weird, or blank and not have anything to say. He has already met my mom really briefly; it's not a big deal to me, I'll introduce her to anyone I don't fundamentally dislike... so I'm just wondering if it's the same for him. 
Thanks.