I'm so glad he's okay now
Honestly, and this is just my opinion---An experienced toy dog breeder should have known to watch for signs of your male overexerting himself and stepped in and seperated them for a while, giving him a chance to rest and maybe eat something and calm down

I know you said that you trust this person, but I'd rethink that one. I'm not trying to put her down or anything, but she put your baby at risk with her lack of knowledge of the breeding process and that's inexcusable for someone that's supposed to be an experienced breeder. Thank God he's okay now, but it could have been the end of his life
Hugs to you and little Mr. Hot Rod