Can Deter for coprophagia in dogs be dangerous? My 1 yr old dog just unexpectedly died from internal bleeding?

My 1 yr old dane mix was eating my coonhound's poo so I fed the coonhound Deter. A frew days later the dane who has a VERY healthy appetite quit eating but I attributed this to the Deter and didn't worry. When a few more days went by and he still wouldn't eat and was losing weight I took him to the vet - who said he had a gastric ulcer and possibly Addison's disease (we get the results tom.) They kept him for 3 days with an IV - his electrolytes were low - and his 2nd night he actually ate so they sent him back home. The day he came home (yesterday) he looked anorexic but happy, then this morning I found him laying in the rain and mud and he tried to get up and fell over. We took him to the emergency vet and he began to have bloody diarrhea and they kept him and tried their best for a few hours but he bled to death. He has not gotten into any kind of poison and has always been healthy until now - and the timinig with respect to the Deter seems fishy. Any possibility it is related?