I don't know about the singing, but your little brother stole the show. lol

Okay... the singing. I like how you had fun with it. That's really cool. Before I get to the singing part of it, I want to address the recording technique. I suspect you're using a USB mic. Probably not much you can do about it, but I think it could've been better had you gotten the guitar closer to the mic, or plugged the guitar into an interface. Would've also liked to see the both of you closer to the mic - I think the vocals suffered a little bit due to poor recording technique. I also got the impression the gal was reading her lyrics. It's a little hard, I feel, to put emotion into lyrics you don't know - plus, it came off as though she was reading. Also heard a couple of minor pitch issues with both of you. Not real bad, but I did hear it. I think both of you could continue working on this, improve the pitch issues and do some singing together.

Oh, and perhaps include little brother in the act somehow.

Nice job. Thanks for taking the time to record this and put it out there for us to critique.
thanks for the feedback man. yeah I see the pitch issues AFTER I sing it unfortunately haha