My wife is also fighting brain cancer over here in Australia. She is doing well and I hope you are.
I don’t have a joke. But what I do have is something we did with our kids (Isaac 7yrs, Nathan 6 yrs and Tia Rose 3yrs), we wrote a little book called Pooetry In Motion…yep it is funny little poems about…well you will need to read it.
Obviously if it is a bit too racey for the USA we do understand. Australians are a bit crude - but we love it.
Good luck with your battle - you clearly have a lot of people rooting for you. And 5000 jokes will make the world a better place.