Q; people who have OES or live in/near Bury

Just wondering if a bug is going around or if breed related.
My cousin has had the breed for about 20years, she currently has 2 Old English Sheepdogs brothers (1 rescued), 1 of them keeps producing too much acid/bile and vomitting after food.
The first time was in December the dog was put on 2types ABs for a couple of weeks and was then fine untill last week, prior to going on ABs and anti sickness meds he did have bloods and other investigations, nothing showed.
He started again last weekend, again bloods, xrays etc. nothing abnormal he as been put on zantac and ABs and seems to be improving if it persists he will be having an endoscopy.
Any Ideas?