Right now your horse and your barn owner are a hostage to you. You refuse to call or make any effort to go see your horse. You say that your barn owner yelled at you years ago about the dentist and it was very triggering because she was yelling at you because you were disabled and couldn’t afford it?? Seems to me she was trying to get through to someone about a horse she has to see and care for every single day. Dentistry isn’t a nice to have horse care item it’s necessary. So my question is was your horse in pain? If their teeth aren’t done they can cause open bleeding ulcers in their mouths. Is every single bite of grass/hay/grain he’s taking painful and has been for years? Or did your barn owner bite the bullet and pay for the dentist herself so she doesn’t have to watch your horse struggle.
If you were so horrified about her trying to get through about the dentist how do you think she feels about approaching you about a conversation about euthanasia? I’ve stood next to a dozen barn owners looking at an old retired horse in their field and had them say if he/she were mine I’d put them down but the owner isn’t ready. You have no idea what she’s thinking. You have NO IDEA how your horse is doing. Go see your horse, talk to the barn owner or go to therapy to talk about why you can’t do either of those things. Forget euthanasia at this point you can’t take any action. Did you think the suggestion would be a magikal money tree that all of a sudden pays your horse’s bills? You may even actually find that if your barn owner will take over care but you have to talk to her. Right now your horse is more a figment of your imagination that costs you a grand a month.