
They had 7 kids there are a pair a twins who were feeding rotten food to the omega as a experiment? as the omega was unable to taste food. Also the father feared that his children who were all mostly dominant alphas would become even crueler, so he separated them from the omega. But i believe it was also due to jealousy of the omegas attention being shared to the children other than him. Omegas in the universe chain the alpha to them, these alpha's brains deteriorates without an omega i believe.

Yea the twins i just didn't feel like adding that, the dominant alpha's own pheromones deteriorate their brains which is why there are sex parties as it helps alphas relieve themselves. Also I'm not sure how severe the bullying was but Greyson mentions an incident in which an alpha fucked a dog because they lost their mind. Greyson has a rottweiler so yea, just speculating, it might just be one of his alpha friends.
This reminds me of a omega universe 'franchise' idk if its the right term, but basically the father separated the omega parent from his children, but all his kids kinda became fucked in the head. I think one of the manwhas in the 'franchise' is called kiss me you liar.