Friend tells me she thinks she's pregnant, but I know her boyfriend is fixed. Should I tell her?

Ok so one of my friends calls me this afternoon and says test came up positive that she's pregnant. Shes gonna see a doctor before telling her boyfriend. The thing is that her boyfriend is a long time friend of my brothers and I know for fact that he got a vasectomy after he had his second kid with his ex girlfriend. My friends a bit of a slut and I have no doubt that she cheated, but I know that vasectomy isn't 100%. Is it my place to even say something to her? Because I know if she just walks up to him and tells him she's pregnant he's going to think the same thing and explode.