Once you sell or part with something, you lose any control over it. No matter what any purchaser may tell or promise you, what you have sold them is theirs to do with as they wish and you will be unable to do anything about it. Many purchasers will tell you all sorts of tales just to keep you happy - sometimes if you meet them before you make the sale, you can get an idea if they are genuine or not, but often they still pull the wool over your eyes. They say buyer beware, but I also think 'seller beware' also applies.
Have your buyers actually been to see Sweety and Beau? If not, how do they know that Sweety is a mare that they will be able to get on with and not just a mare that they will 'sort out and train'? And little Beau - have they seen him? Do they have the experience to give him a chance or have they spoken to their vet about his possible future? How are they going to work with and train Sweety while she is still feeding and caring for Beau? Do they have somewhere to keep her apart from their other horses so that little Beau doesn't get 'overworked' by being introduced to a new herd with all the running and chasing that will go on?
More questions for you to ponder Jenny. Many years ago we had a foal who was wrong in his make up. We kept him and cared for him and when we weaned him he was happy with all his other weaned buddies, but with his special care keeping him comfortable. Not long after weaning the vet told us that he would need many operations throughout his life to even keep him comfortable and that it would be hard for him. So we had him quietly put to sleep - they dont know what is happening and it was our 'gift' to him. We still miss him so much as he was such a character, but we know that we did the right thing for him in his particular circumstances.
You have had a lot of problems with your foalings this year and this can be a strain on the most experienced of breeders, let alone one just starting out, plus there are your own individual 'home' circumstances, so I know it has not been easy for you Jenny. I do think that you should give breeding a miss for a while and just enjoy, love and care for those minis that you have. Maybe the time will be right in the future to breed again, and this time perhaps it will turn out better for you.
Meanwhile, we will all be here for you, so keep giving us news of your girls and the babies. We have lots of new foalings to watch over and to chat about, so lets look to the future and continuing friendships.