I'm sorry I don't know what to do either.

Dogs do change when they get older. You might want to have him checked out medically see if anything is bothering him. But if he's starting to go after small things like that, you should do something soon before he goes after you.

I'm not saying he will go after you, I don't know much about dogs. But I do know that dogs do change when they get older.

I wish I had more info for you.