Windsor the Cat medical bills

Our cat Mr. Windsor Black was a stray my boyfriend and I rescued. He's been very adamant on going back outdoors but we managed to keep him indoors for 6 months until a few days ago when he snuck out and went missing for 3 days. When we found him and brought him home he was not in good shape. I brought him to the vet this morning where he's being treated for a bacterial infection raging through his body, 106 fever, an ulcer in his mouth, gash above his left eye, conjunctivitis in his eyes, upper respiratory infection, infected paw which may be a broken paw. He's covered in ticks and also has tapeworms. Everytime we thought we got all the ticks another tick popped up. Today's visit was $293. The vet anticipates many more appointments and she is worried he may have FiV. My boyfriend and I are struggling financially so any help is much appreciated. We just want to get our little boy cat healthy again.