I'm sorry that this is happening.
A rise in lipase usually indicates pancreatitis or gi issues or maybe nothing at all. After that came back high, the next step maybe should have been a Spec cPL. Numbers under 200 means no pancreatitis, between 200-400 means possible and over 400 means that's what it is. If it is over 400, there is really no guessing.
They saw nothing besides the pancreas issue on the u/s?
That is odd that he isn't pulling out of this, especially since he isn't vomiting.
Are there ANY other abnormal levels on his blood work (even high or low normal)?
With pain, gas, high lipase, high amylase and a u/s confirmation no other disease really makes sense. Are they running blood work for things like EPI?