I'm sorry Rico has cancer. Why do these things have to happen?
If you think he would benefit from better nutrition than baby food, have your vet order some LaFeber's Emeraid Omnivore. It is a powder you mix with water to however thin/thick you want and feed just like you are doing with the baby food.
Since cooler weather is coming, a heat panel that attaches to the cage or an oil-filled radiator to keep him a bit warmer would also help him be comfortable. Some people prefer a heated perch but I've never tried those.
Also speak with your vet about medications for pain control, maybe something like Tramadol.
And most of all just give him the comfort of your company. Try to avoid being upset as much as possible as they are influenced by your moods. (Yeah, easier said than done, right?)
Many hugs to you both!