Small duct Psc vs Classic PSC symptoms

Hi Joki . My son 19 years old has been sick off and on since November of last year. He started with nausea, vomiting, diarrhea and became jaundice after I picked him up from college. His main common bile duct was dilated , pancreatitis with elevated amylase and lipase. Fever . He was in the hospital for 7 days and was diagnosed with acute gallbladder infection. Started him on Flagyl and Cipro and he started feeling much better.
We got discharged from the hospital but as soon as he stopped talking ATB his symptoms would come back fever elevated liver and pancreas enzymes. He had a gallbladder removed in January of 2020 so they did a liver biopsy then too which was normal. Because of over use of ATB he developed a c diff which is only treated with oral Vancomycin as soon as we started it he started feeling better. After 6 weeks we checked the blood work and the enzymes were normal, but 4 days later from stopping it his symptoms would come back and the enzymes would go up .
He had 3 ERCP, 3 MRI , two abdominal cat scans , US all normal.
He was tested for all autoimmune liver decease all negative even PCP caused my autoimmune pancreatitis was negative IGG4.
About 2 months ago we stopped Vancomycin po and started URSO 300 mg three times a day and it was working for 2 months liver enzymes went back to normal, however he started with stomach pain and symptoms came back again. So he had ERCP done last week and the doctor said it is consistent with small ducts PSC.
We started him back on Vancomycin again and his dose is rather small 125 mg twice a day but we know this does works for him from before.
He had colonoscopy and endoscopy both normal so no UC or bowel problems .
Any advice for us ?
I thank you so much.
Desperate mother