Any opinions will be great!!!

So about a month ago my brother in law stared dating a 41 year old lady his is 43. He is single with no kid and desperately looking for a mate to start a family. So about 2 weeks ago he announced that this lady is PREGNANT!!! We are trying to be supportive but its just to weird that he just met this women and now she is pregnant she has kids they are teenagers. I just can believe that this woman is actually acting like a 15 year old and not use protection with a man she just met... Does this sound suspicious?????