Mother sent awful email about my Fiance.

Sorry for the long post. But Im really conflicted.

My fiance worked with my mom in a small office, just the 2 of them, the owner and a few sales guys. They were kind enough to give him the job for experience and to shadow the sales guys to see if he would like to pursue that come his graduation.

Anyways, he decides its not for him (this was clear to everyone) . He puts in his 2 weeks and starts looking for internships. One day he has to get on my mom's work email because she was off and he needed to process something (idrk). He sees an email with his name as the subject to her Bf. He reads it. It's awful. They said so many mean things about him. He's a great guy and is not rude or lazy so idk where what they said about him came from. Her BF called him a piece of shit and lazy. And other really terrible terrible things.

I've tried to talk to my mom about what she thinks of him. Because clearly she has some issue with him! But she won't budge. She just keeps saying she really likes him and he's sweet. I ask and ask for her honesty and I don't get it.

I know he shouldn't have read the email. But I know I would have been too curious too. Would you confront her? I can't stop thinking about it because of what they said. I'm so mad and confused.

EDIT: I should add that my fiance asked me not to confront her about it. He doesn't want her to know he saw it.

And their opinions don't have an affect on our relationship, I just don't know what their problem is with him! He's always been there when she needs help and has never been an ass. Im just so pissed.