Advice needed for biting dog
Let me start off by saying that I have done some reading on the subject already and given my limited options, I'm trying to find out if anyone else has had this specific problem and knows what might work best.
We have two dogs and both are small, neither is a puppy, and both are essentially rescues. We got both from other people not from a shelter and overall have not had any problems from them aside from one liking to bark at things that aren't there, and the other ones biting. The biter is a chihuahua/Pomeranian we believe, and is around 3-4 years old. We got him two years ago and he was a little skittish but overall friendly; he loved playing with the kids (we have all ages), he didn't growl when people approached his food dish or toys, he loved playing with the kids and being pet, and aside from being a little high pitched we had no problems.
The problem came about when my parents took a trip out to Missouri to help deal with funeral arrangements and the possessions of my grandmother. The biter (Dean) is SUPER attached to my dad and when he was gone he had some regression issues with deciding he didn't ant to be housebroken anymore. This lasted a good long while but eventually a new problem popped up which was his sudden hostility primarily towards the younger kids. He started growling more, occasionally even biting them. Rarely did he break the skin though sometimes that was because clothes were in the way. He occasionally would bite the older people but generally he didn't. This is long after my parents got home and before we got our second dog. Suddenly he was territorial over treats and would snap at people that got too close while he had them, and we couldn't figure why.
No major household changes occurred during the time he started biting, and nobody changed how they interacted with him, i.e. kids yanking on his tail, toys being held hostage, being ignored, etc. Everything stayed exactly the same and yet his behaviour changed. We can't find any triggers since sometimes he doesn't mind being near the kids and sometimes he does. He is currently in a muzzle when he isn't on a leash near the food and water or in his crate, but ideally we would like to get our old dog back.
I know at that age with this problem the simplest solution would be to take him to obedience classes, but quite frankly we can't afford them. We are looking for something we could do that a class might instruct us to do, that will teach him not to bite, ideally without requiring us to be bitten repeatedly like with bite inhibition training. The little ones are already fraud of him when his muzzle is off because they don't know what he will decide to do, so just letting themselves be bitten and yelping or ignoring him wouldn't exactly work for them.
Any advice would be helpful and the more the better sice not all methods work with all dogs.
