What should I write on his pre surgery card? Any advice?

My husband is going to have his micro tese surgery Thursday morning and for those who don’t know it’s a surgery they preform when a man has no sperm found in his semen. They go in and look for it internally with only a 40% success rate. This is our last hope of having our own •biological• child. We are both really nervous and scared. But we know if they don’t find any we will do a doner. But obviously we really want this to work. I got him a little card to give him before the surgery and not sure what or how to word everything. If you have any ideas let me know thank you.