Help Save Rascal!

Rascal has been very ill. He has been puking blood and no one is sure why. I've been trying to take him to a vet for years due to issues with puking (but never blood), as well as to get him groomed. This is the third time in a month and we've only once taken him to the vet for bloodwork and the bloodwork told us nothing. He has been very strong, he's been eating and trying his best to recover. I want to help him so much, I don't want him to die while he is still fighting for life. What would need to be done is x-rays, another test, and likely surgery to remove/fix whatever is causing him to get sick like this.

Before all of this he would get in lots of trouble (hence the name), was a huge fur ball of fun ready to play with anything, loved to be pet kindly and gently but would sometimes get rascally and change his mind to play halfway through. I just want to give him a fighting chance at life and I don't have the personal funds to do it. Please help, anything at all helps.