Ishmael... again

Ishmael stopped eating again over the holiday weekend and was isolating under the bed. I took him back into the vet and he has dropped another 1 1/2! He's down to just 9 pounds now and he still isn't eating. They ran the same damn test they did on him last time, only this time they sent the x-ray that still has a "shadow" on his lung. The vet used the very vague term, "pathology", over to some kind of specialist and apparently they weren't entirely sure either. So $1,000 later and all I know about my cat I already knew, that he's very sick and probably dying. So of course they just want to do more test (more money) and then what... tell me he has cancer and he's dying. I already know he's dying. Shit!!!!!
So last night as I was stewing about what to do: nothing and let nature take it's course, stick with this vet and run one more test, switch vets and get a second opinion....
I typed his symptoms into google last night and you know what? I think I have diagnosed him. He has heart disease. I'm pretty damn sure. That explains the weird rear limb weakness ( we were thinking why would he have rear limb weakness with pneumonia... I ask the vet about the rear legs and he pretty much ignored me). His other symptoms: initially he was coughing and vomiting bile, rapid weight loss, lethargy. He was diagnosed with pneumonia and seemed to get a little better with antibiotics, starting eating a little but we also noticed he seemed to favoring one rear leg over another and then he got sick again. He is coughing a little from time to time, I mostly notice it at night. He seems very weak but so far he doesn't seem to be in pain. He is not eating, even with appetite stimulant. So I'm taking him to a new vet on Monday for another opinion. It's probably too advanced and there won't be any thing to do but at least I'll feel like he's getting better care and I'll be getting some better advice (other than do more tests, spend more money, we don't know!). Lame ass vet, I'm very disappointed. It's either heart disease or cancer and either way he seems pretty far gone at this point, I don't expect he'll live very much longer. I just hope he stays comfortable and happy and will just pass away in his sleep.
My poor sweet little Ishmael.
I'll scan some pictures of him. He's a beautiful cat, smart, loving and loyal.