If you can try to find a good farm vet. We have one that doesn't have the fancy office and is actually almost never there but out in the field with his clients but they tend to be a bit more practical in their treatments. Ours is very understanding of financial limitation and honestly we were...
you might try giving him oil straight. I had a lab who tended to gulp anything in his path. Food, clothes, sticks.... it really didn't matter. As a general rule he had a ton of tummy issues and puked all the time. Whenever he ate something he wasn't supposed to the vet had us give him a table...