Help Okoge get home

After nine years in Japan, I'm going home to the USA in April, and he's coming with me! On this I am determined!
However, between the surprise of his ticket price home and a few medical bills I've had personally, its a BIT tight now. In addition to all this, I've still got his vet bills to think about, and any fees I might encounter.
Any little bit will help! This furball has been with me for seven years after a sad backstory; Okoge was the companion of an elderly man, who had to go into a care home. The care home refused Okoge, and so did the man's family. Okoge ended up at Animal Refuge Kansai, and then he found me after seven months at ARK. No one really wanted to take him on, since he's a special needs kitty (vestibular issues so he wobbles a LOT), but he wouldn't let me walk away from him. I can't give him up, and I won't.
But I'd be so grateful for a little bit of help in getting him there.

Why does this cost so much?
I finally checked into this a little deeper. United's cargo rate from Japan is $1,000USD. They told me when I first looked into this that his fare would be at least 150% of the cargo rate, which does take me up to $1,500. Then there's the pet rate which is, surprise!!! About $250. So there's the break down of the cost. 

Why fly United and not another airline?
Between Kansai and San Francisco, there's only one direct flight, and its United. Every other flight is 18-29 total hours and requires a stopover somewhere. Finding a hotel to accept him and everything is a stress I don't want to out on us.
He's also special needs...He has a vestibular disorder that makes him wobbly. So the less time traveling, the better.

Thank you for reading this far! I appreciate everything!