Are they related or not?

Okay so, there is my friend and her name Maria. And there is a boy named Jason.
Jasons mom is going out with a man. That man is Maria's mother brother. So Maria's mom and the man whom Jason's mom is dating are brothers and sisters. But they arent married. They are just dating. Is Maria and Jason related? Or are they cousion or no?

Sorry I tried my best to explain it.

Look it all depends if they are step sister/brother because then they are not related by blood so its okay to go out and get married. But if they are true brother and sister than YEAH of corse they are relate. So jason and Maria are cousins!

The way I understand it, is that Jason's Mom is dating Maria's Uncle. But they're just dating, nothing more.

At this stage, no, they aren't related. If Jason's Mom and Maria's Uncle got married, then they would become cousins by marriage (1st or 2nd cousins I'm not sure), but they could never be blood cousins.

Sorry I didn't understand the way you wrote the information. So just ignore what I wrote yesterday!

Okay, thank you guys. And I'm sorry, it was really hard to explain..

basically jason's mum is going out with maria's uncle.
they're not married so jason and maria aren't related.

if jason's mum and maria's uncle were married
maria and jason would be step-cousins.

I had to work that out, but I've def' got the right answer.

thank you so much