[YorkieMother]

No one here is qualified to work at this level of concern but I would suggest that you get your dog and you to a behaviourist as soon as possible.
No of us here to my knowledge are board certified in behaviour.

This is not a training problem in and of itself.

Any vet school should have one. If I get time later I will go have a look as to who is in your state.

Alpha work will not work with what I am thinking this is and the best course of action is higher level help then a trainer that not pacikng a PHD or a DVM with behaviour.
Wonder how you have worked training him and just how consistant you are.... no blame I not thinking it is your fault. but tough love on a wrong wired dog will make things tougher... I am thinking I am seeing a wiring in the brain concern.

In the mean time you need to keep him away from the kids and get him working on the nothing in life is free protocal and no bed.

As for a muzzle good idea if he has been desensitized to it for safety but not as a punishment.
I also see if you can up his time doing things to get him more tired... not over tired though.

JL