Please help my rescued flamepoint will not stop crying and I am worried!

I took in this cat in July of this year.. it kept crying.. stray outside my apartment.. I felt horrible.. fed it.. took it to the vet where they charged me 52 for antibiotics and to tell me this is a 5 to 6 year old flamepoint that is neutored... asked if I would like to get the feline aids test.. was too much money and I just thought that he was well taken care of and is just sick with a respiratory disease. Its like 4 months later... and I brought him inside with my other cat Mary. They hated each other at first but now they lay next to each other and play hide and seek and playfully fight. What i am worried about is that he drools when laying on me and breathes loud.. seems as if this respiratory problem or whatever it is has not went away. I am really scared that theres a possibility he has that feline leukemia. I love this cat... please help! Also he has excessive calling... he seems to cry all day long!!! No matter what. I spoil him with wet food.. always feed him.. what am I doing wrong. Also the other night I woke up and he got so startled he jumped literally 5 feet in the air and ran so scared. He jumps to every loud noise there is. I am seriously broke and cannot even afford the vet I do not know what I am going to do. I fear that this is serious and my other cat Mary might be in harms way... any thoughts???