Help Me Save My Cat Mel’s Life URGENT

 Mel is a complicated feline I rescued from what I assume was a rough situation that landed him on the streets three years ago. Mellow quite literally sprung into my life one winter day when he was abandoned outside the library I work at. Basically, he just kept running into the building after spending the morning staring inside. He kept getting thrown out until I came in to work and got him to approach me. Fearful of humans and not in great shape, I decided to take him home despite his aggressive behavior, and with time he and I forged a bond everyone told me was impossible. He is the tail (see what I did there?) of the library, remembered for his ever changing antics and behavior - and the wounds I recieved in earning his trust after I took him home! Now, he's getting very ill very quickly and it's been a struggle determing what is causing his decline. I have been talking extensively with my vet and he thinks it could be IBD or Chronic Pancreatitis - unfortuantely, the two often occur simultaneously. It's also more possible for him because he went through a severe atypical tapeworm infestation.  Mel spends most of his days in aberect position curled up and staring off, half awake - when he's not passed out. I was going to go House on him after many an email with my vet and treat possible causes etc, but I alos very much want to get the proper tests done and have funds available for treatment etc. He could be in a lot of pain and, undiagnosed, this could be fatal. My goal is meager considering all things and I no longer have time to play around with this. I have until Monday and then I just have to go all in on my own.