Dionne.... i tagged some members to hopefully help and provide some support in your decision. I honestly do not know what I would do, but in reading your post (several times) and the stress I am feeling tells me it is overbearing for you.
First the small thing -- the shedding could be from the food you are feeding or just the time of year it is does he have allergies? My girl is just a heavy shedder, but it did lessen some what when I took her off a chicken based food and placed her on Fromm grain/chicken free food.
Now, the big item, knowing the love you have for Bustys and you want what is the absolute best for him, it might be you know your decision. The more I read the post, the more I lean to having Bustys stay with your trainer and work him back into your home when you are capable of caring for him. all this stress just is not good for the health of the babies and you... also, all the changes in such a short time could have a negative impact on Buster... you know how OCD they can be. allow him to be a happy boy at the trainers home and you can go visit alone or with the babies and then when the time is right slowly, with the trainers assistance, you can work him back into your home. It may all work out in the end that he stays with them, but at least you know you did what was best for everyone's health, including your own.
hugs and many prayers for you !!