Thank you guys so much for your kindness, honesty, and explanations so far. I definitely will be asking the vet more about how he generally does things and will get more figured out with the people who will pick him up.
I also definitely would insist upon staying there with him, even if we have to find another vet to do it (though I'm pretty sure our guy will allow it). I just couldn't stand to leave him to go through that among only people he wouldn't know well or trust. This particular horse has had a lot of really terrible experiences with people for most of his life, so to me it's extremely important that he's among a trusted friend on his way out.
And Phantomcolt, don't worry, I've read a lot about that and actually even watched videos of just what you described (because I figured better the first time be a horse I don't know than our guy) so I understand. Thank you for being honest
I'm doing pretty well with everything at the moment, I suppose disassociating to a point, though I'm sure that won't be possible once the day comes.
Honestly I'm glad he's at least made it this far with us, long enough to learn to trust at least some humans again because he was really
badly abused before we had him. It took him a long time to settle down, so I'm just glad he stuck around long enough to meet kind people and got to have some really nice, calm last years of life. My mom right now can't even think about it, but I'm going ahead and starting with the planning, mentally, and feel pretty at peace with things. It really is so much better for him than having to keep on living in pain.
Anyway, thank you guys again.