Thanks, he's my baby. :)
As far as his foals, maybe he's never been crossed with another frame carrier? Or if he has, maybe those foals were the lucky 75% that were not homozygous lethal. You can't take just him into account, you have to consider both sire and dam together. It's not just one copy of the gene being passed on, one copy of the gene HAS to be passed on from both parents to be lethal so both parents must be carriers.
There on the tips of fair fresh flowers feedeth he; How joyous his neigh,
there in the midst of sacred pollen hidden, all hidden he; how joyous his neigh