DS would always get upset about broken crayons too. To be honest, it wasn't a battle I chose to fight. I stocked up on crayons when they were cheap during back to school season. I would empty a couple of boxes into a crayon bin and store the others. DS insisted on bringing home all the free crayons from restaurants and events and those went into the bin too. We tried taping broken crayons, and like you found, it's a short term fix. There were so many crayons in the bin that I didn't feel bad about just throwing away broken crayons.
For us, the lesson became: sometimes things break. Some broken things can be fixed and some cannot. If something breaks and cannot be fixed, you either deal with it being broken or you throw it away.
DS also gets upset if toys break and cannot be fixed. Several times he has chosen to throw away an irreparable toy after we talked about it. This has always given him a sense of closure and allowed him to move on. I have always respected that, even when I personally disagreed with the need to throw the toy away.
I'm not saying that this is what you should do, just that this is what worked for us.
Gena
DS, age 11 and always amazing
“Autistics are the ultimate square pegs, and the problem with pounding a square peg into a round hole is not that the hammering is hard work. It's that you're destroying the peg." - Paul Collins, Not Even Wrong