FOR all you german shepard owners

I need to know...ANy of you here that own german shepards, is it true that they have sensitive stomachs or tend to have gastro issues???

I have friends that have a female long coat shepard, got from a rescue about 5 months ago, she is almost a yr and half old..this dog didnt seem to have any eating issues or throwing up issues when in her foster homes, but since being with her new family  , she throws up bile here and there or just throws up....she was eating TOTW with her foster family and was great, this new owners dont feed her that anymore due to thinking it was recalled before...they take the dog to penn vet hosp in philad. pa. for her vet care, and already had ultrasound done cause she throws up here and there, they found nothing wrong, said she was great and a healthy dog...and if she is getting sick  may be something she is getting in to in the yard or in the house......so vets told them to try royal canin for GSD, but dog didnt seem to like that, now they have her on the rx  ID  hills, she eats that good...

so they made an appt for her to be scoped to be sure esophagus and all that area is fine...they been giving her prilosec script too and it makes a hell of a difference in a good way..so before they continue to give her that they want to be sure all is ok....

this couple had a shep for 12yrs and he died a few yrs ago,  then they got a new pup from a breeder a GSD and he had to be put down before he was even 2, he had so many issues all similar, and all tests done only to have gotten throw up backed up into his lungs  and got the pnemonia and was so bad he had to be put down....they absolutely adore their dogs, they are like their kids, cause they dont have any.....but sometimes when i hear how the dog they have now, regurgitates , i think...what the hell is going on.... they are so paranoid that this dog will be sick last dog, they micromanage her, they have a fenced yard all wood so she cant see out but can hear the dog next door to her in yard, so the man thinks she may break her leg or something if she is running back and forth along the fence barking at this dog.......short of saying back off and stop hovering over this dog, i dont know what to say...........how does she get along with other dogs in her foster homes and eat well, then she gets adopted to this couple, and they feel she doesnt like other dogs cause she barks all the time at them, and now seems to have stomach issues or food issues....the wife is a registered dietician so she knows that allergies can play into it, but they try all the grain free stuff, then vet says grains are ok to give dog...its like your head is spinning you dont know what to think......

thats why i ask here, anyone who owns GSD and knows this breed, any feedback you can give me???   id love for their dog to meet mine, but he wont let that happen, and its sad they dont socialize her much except just them