I have a liver shunt baby that started having problems as soon as we brought her home at 10-12 weeks. I suspected liver shunt but the vet kept telling me I was wrong. She never had seizures or any other HE signs...she was just a picky eater, very small and didn't seem to have as much energy as I thought she should - such as sleeping too much! I kept asking them to bile acid test her and I was told it was not necessary. Finally, at only just over a year old when she was supposed to be spayed, I insisted on the BAT, and her numbers were really high. We had the surgery done to correct the problem and she is now 5 and doing great. If you suspect liver shunt, your baby should be on lactulose and a very low protein diet. I have to be at my daughter in law's birthday dinner in 45 minutes tonight or I would write more. Please go to this website...I think it will be a great help for you concerning diet, etc. There is no harm in changing to a low protein diet right now to see if he improves...
Liver_Shunt_And_MVD_Support : Liver Shunt & MVD/HMD Support
I will check your post later! My thoughts and prayers are with your baby...