[URGENT] Help Milky the Cockatiel

Hi, I’m making this fundraiser for my cousins cockatiel. Milky is a very energetic bird loved by many, he suddenly got very lethargic after coming back home from babysitting. His symptoms include vomiting, very runny droppings, and barely singing or moving. He’s always sleepy which is very unusual for a cockatiel and as you may know birds do not show symptoms of being sick unless it’s truly serious. The first time he started throwing up he was taken to the vet immediately who said it was nothing serious and that he should be fine. Yesterday, out of no where he became very weak, chews very slowly and still trying to regurgitate/ vomit. His behaviour is very unusual and we’re very confused as to why the first vet didn’t do an extensive checkup. My cousins parents are unable to afford a second examination or the treatment (tests/medicine) which can get very pricy. It is also very difficult to find a professional emergency avian vet in our area a good one is at least an hour drive away. I’m very worried for him this is super urgent and I honestly don’t know if he would may it the next few days, any help would be appreciated please and thankyou for reading.