OP, do you have an actual verified paper account of who his dam and sire are?
If not, he is not eligible for registration anywhere, not QH or Appendix or WB. You cannot even make any truthful claims as to what his cross is. Any savvy buyer will want to see papers. You have a grade horse without papers or a clear history. Happens a lot actually, horses separated from their papers or not registered at birth.
I can see why you don’t want to sell to your trainer. She wants to keep you paying the expenses for another six or seven months, then give her the horse for free.
I suggest you tell her that you need to sell the horse now, and are going to actively pursue this.
First you need to “stick” him so you have a true accurate measurement of his height. Some buyers want smaller, some want bigger. People who are determined to get 16 hands plus are going to be upset if they drive out to try him and he turns out to be 15.2.
Then you put up a sales ad that says:
Project horse: xx hand high gelding, eight years old, nice movement. Goes walk/trot/canter, started lead changes, has some exposure to small jumps. Still green with some quirks. With miles, would make nice low level hunter/jumper mount. I bought him as a project xx months ago, and we have done extensive work on his ground manners and some work under saddle, but I don’t have the time or funds to carry this forward. He would be best suited as a project horse for a trainer, or for an ammie with strong support from a trainer. Not suitable for a child rider at this point. No papers, sold to me as a warmblood, cannot verify this.Asking $3000, open to offers. Motivated seller.
Accompany this with a good standup conformation shot and a short video that shows his best walk, trot and canter on a relatively loose rein, not bolting or frantic.
Take the first offer of $2000 that comes from a competent trainer. Refuse to sell to clueless mothers who will be posting on COTH in six months “why does my child’s horse bolt?”
If your trainer makes an offer or even says she will take him now in mid winter, sell him to her.
Every month you pay board on a horse you don’t want, his total cost to you is going up and up.