Help Snap Get Critical Health Testing

My cat Snap is about 6 years old and one half of a bonded pair with his brother, Slim Jim. He has always been a cuddly, playful cat with a big appetite, but recently his health has quickly deteriorated for unknown reasons. He went from 12 lbs to 9 lbs in the span of a month, and has been vomiting almost every day. Our family has recently experienced severe medical issues and financial hardship, and needs assistance paying for specialist testing for Snap. We specifically need to get him an ultrasound to screen for cancer or other explanations for his health issues.