@barbarn, At the end, I am going to post the link about cyclosporine. I realize that this is more that enough to scare the daylights out of you. But, it is a powerful medicine, and it must be taken according to strict adherence to the directions. It is used for conditions other than transplantation, too. It is also needs to be carefully monitored to prevent harmful side effects.
I do not take cyclosporine, but I do take another medicine that has the same warnings and precautions. And from what I have been told, many of the problems come with long term usage. (That is why transplant patients are closely monitored for the level of these drugs in our body).

I think that you should talk to his opthamologist about his glaucoma. And that you should talk to the prescribing physician about the pros and cons of his treatment. You might want to print a copy of the information, and to highlight the parts that concern you. Take it with you when you go for next visit.
Another good resource is your pharmacist.

All medicines come with risks. I think this is a risk vs benefit decision. Without other options for him, buying more time sounds like a good idea.
What are his thoughts on this?
Before I close - I have been taking my drug for 9 years with no serious side effects.
https://www.mayoclinic.org/drugs-supplements/cyclosporine-oral-route/before-using/drg-20075815