Welcome to the board, Maggie221.
I'm sorry you have to come with the problem you present.
First of all, go to the hospital and be with your uncle. The JW religion tries to be family, but only real family can give support emotionally, imho.
Even if your counsin signed a "no blood card" and he is an adult, you can tell your uncle that JW's don't get disfellowshipped, kicked out, of the religion for taking blood. Unfortunately this is not the time to get into the details on what JW's allow and don't allow because it is all based on nonsense. Please see the website quoted to you, it has a lot of detailed medical information.
If the worse happens, JW's have funerals for their members and of course everyone is welcome to attend. But be forwarned that it will be a sale's pitch for their religion more than morning about the loved one.
I say do what your heart says to do for family. That is love and maybe your uncle will remember the love shown him by his family.
Hugs,
Joy