This would bring up an argument that is in every other breeding thread. Why? Why bring another foal that might have the right conformation because one person told you that your mare was decent if you found the perfect stallion. If you wanted just to get a decent grade foal then you could just buy one and not potentially risk your decent mare's life.
Realistically, no. Hypothetically, no. I don't really know what he really saw in her. I know plenty of mares who look exactally like her. Yeah, she is cute as any horse, and I don't know if she has a good personality or not but that really doesn't intirely matter when it cpmes to breeding.
If she is a great horse, then you shouldn't risk it. Risk the chance of complications or having an expensive foal that you cannot even use because somewhere it conformationally took a nose dive.
I have a mare with a long back, long pasterns, and a big head, and my mom decided she wanted to breed her because of her blood lines, and her foal is kick-*ss. Not perfect, but she's by far got what it takes.
Unless in certain situations, I doubt you have to be that dramatic about conformational nosedives in the foal that will stop it from being a good horse, unless you have a breeding business or are in really high-level competition.
Plus, the chance of your mare 'losing her life'? That's 90% about proper care from the owner. This point of view seems a bit over the top unrealistic to me, although I don't condone everyone with a fertile horse breeding foals... there are just so many more factors to it.