A close friend of mine is possibly faking a pregnancy, what do i do?

Hello. As the title reads, i have a friend who is possibly faking a pregnancy. My friend (24) recently came out with the news that she was pregnant. Mind you, the guy who she is supposedly pregnant by is an ex that she has been broken up with, but casually hooking up with him. Anyway, she shows the ultrasound and it seemed very fishy to me, so i google searched it and a whole website to create fake ultrasounds popped up. The page had the exact same ultrasound photo she showed us, same measurements and everything. The only difference was the name, dob, etc. The website allows you to create the ultrasound with your own info. Anyway, i personally know the “baby daddy’s” mom as she was a previous boss of mine. She has always talked about having her first grandchild and has already started buying clothes, diapers and any baby necessities. She cried her eyes out at the news and is beyond ecstatic about this child that doesn’t even exist. Now, this friend of mine has stated countless times that she is afraid of a miscarriage. Why even think about those things this early on? Also, the ultrasound she showed us has a fetus the size of a 2 month old…she states she’s about to hit a month. My question is: how do i confront this problem? i don’t want the ex’s mom to grieve a miscarriage of a baby that never existed. I know if i confront her, she will not tell them she was lying. Do i confront them? Please help me as i am so conflicted.