The way things have gone in Ireland, you are going to struggle to get anybody to come out and have a look at them. The ISPCA is overflowing with unwanted horses/donkeys and neglect cases are flowing in like a river. There are horses being left off on roadsides/in bogs - there was a story about a donkey shot in the head and left to die in a bog somewhere in Meath - he ended up being rescued by a place in ballivor but died from his injuries. There was another story of a mare, also found in a bog, with a broken leg and left to try and survive.
I think, as hard as it is going to be, you need to step back and let them sort their own pets. If you keep helping them, he's not going to see anything wrong because they won't lose any condition. You've done your best to try and educate him, just try and be there when he's ready to listen.