Cousin needs help

Hey ladies I need your input. My male cousin slept with this girl on September 27th 2020, now she's pregnant. Now she said she also slept with another guy a month prior. When she supposedly got an ultrasound at 4 weeks with my cousins baby (which she clames it's only his) she said she was over 9 weeks. Then, she said she was getting a second opinion because that ultrasound was wrong. So when she sent my cousin some picks, 1 month said 11 weeks then over a month later said 12 weeks. She barley sends pictures with all the info until now. Now she sent him a pic of the baby at 19 weeks and it's roughly in the time frame that it could be his but all the other times there was no way he could be his. He's gonna get a DNA test when the baby's born, but I hate to see him stress. I thought they don't do the first ultrasound till 6 weeks?? Please be nice, I just need some opinions. She's claiming now that she might have to deliver early cause of high blood pressure. She said her due date is July 5th. When he asked how early she wouldn't say.