I am so sorry
I will send my prayers to you and Tigger.
Is it possible for you to find a vet that can come to your house and have him PTS at home? I think if ever my pets are at that point, I would try to find a vet that does house call for that one thing. It's less stressful for them to be put to sleep in the comfrot of their own home. Also, your other pets can have the opportunity to say goodbye and know that Tigger passed on instead of them wondering what happened to him.