Help my fur baby Clause live a little longer

My name is Ashley and my fur baby Clause is in trouble. He (along with his brother Boo) will be 18 years old next month. I've had them my whole adult life. Unfortunately Clause is getting sicker and I need to have various tests run in order to get him some relief, or I need to say goodbye soon. My cats are my everything. We are currently experiencing houselessness and live in a long stay hotel. And I lost my main income a few weeks ago so funds have been tight to begin with. My mental health is dependent on my cats. We need help. I need help. Clause needs help. I'm not ready to say goodbye, but I will do what's best for my boy. I just hate that money is what's getting in the way. Please help if you can, thank you