I feel for you as I have a barker. My Teddy will be three in May and is over 14 lbs. He is a non-stop barker and I mean non stop. He barks in his sleep!!!
He has worn a shocking bark collar since he was about 8 months. I had tried everything and I mean everything to change his habit of non-stop barking and nothing worked.
Even now if I take the collar off within an hour he will bark like crazy at everything, TV, me, the water running in the sink, etc..... I keep extra batteries on hand just in case. I did once go a few weeks with a dead battery before he found he could bark like crazy again.
The collar is not for dogs under 8 LBS so if he is less than that you couldn't use it.
I sure hope the can, treats, something works for you as I FULLY understand non-stop barking can bring you to tears.
For anyone that thinks the collar is mean Teddy is my baby boy and he loves his collar as it keeps him out of trouble when the other dogs bark and get told "NO" he gets a GOOD BOY!!!