I think the hardest part is when the spirit is still willing but the body just can’t anymore. Add in someone who doesn’t like a change in routine, or to be helped, and you do have the perfect storm
this is where I remind myself about “a day too soon is better than a day too late”, because I waited too long with a cat who was still very much present, but whose body was giving out. Whenever I start worrying about it being too soon, I remember Richard, and remember it is my job to be the adult.
The gabapentin is worth a try, it might help for awhile, can’t hurt. Jan and Jerilyn have it right, make a plan, so you aren’t faced with a crisis. Conner had his episode (still not really sure what it was) on a Friday night, and being able to talk to my vet that evening and over the weekend before she came to let him go on Monday was a huge help. If you can, letting him go at home is such a blessing for you and him.
Whatever you decide, it will be right for him.