Don't give it up. You have too much to offer; I've been reading your posts for a long time and you have knowledge to pass on. Change the way you teach.
When my urinary system collapsed and then I had heart surgery, I thought that I was done with boxing. I had always been very active in teaching, the way I did mitts and everything else.
But when I couldn't move like I used to, and had time to think, I took my eyes off myself and became a much better teacher than I had been before.
If you still love boxing, it will break your heart to walk away. Take a minute to reevaluate how you contribute and how you teach. Maybe you can't get in the ring and spar like you did, but you still know what you know. Sparring partners are easy to find but knowledge and experience that goes back 60 or 70 plus years is hard to find.