I am presuming that this person is also a female.

If she is a female, you must advise her in a nice and diplomatic way. most probably, she is having a continuous period and she thinks that she must not pray if this is the case.

But if this person is a man, you shouldn’t talk to him.

And Allah knows best

There’s a person who you see every week in class; week after week you notice that this person, who is Muslim, just sits there in the classroom and never prays when every one else leave to go pray.My question: Should I say something to this particular person or not? Is it right to just stay quiet and mind my own business even though I’m aware that this Muslim person is missing prayers on purpose? Is there any sin on me for not saying anything?