I have to say I feel this is totally a Fox Valley 32/40 problem. We have lost far too many babies to this formula. I am almost sure that the large head is a nutritional problem from the FV and not hydrocephalic. Somehow this little has held on to life. Take him off the FV today and get the Esbilac. Frankly I am seeing problems with Esbilac too. If he were mine, I would put him on the Goats Milk formula. I am seeing young babies and babies that are compromised having trouble digesting Esbilac. You are describing some of the symptoms we are seeing with Esbilac in young babies now. I would not take any chances with the Esbilac as he has struggled for so long he can't have any more struggles with formula. I would use the following formula.
3 part Goats milk
1 part heavy cream
1 part full fat vanilla yogurt
Start out with 1/4 strength formula for a few feeding, 1/2 strength for a few feedings, 3/4 strength for a little longer and work up to full strength very slowly. This baby could suffer from refeeding syndrome if not carefully transitioned to a new formula. Goats milk is very easy to digest. Poor little baby is in extremely critical condition.
Please know this is not your fault. The FV should be recalled. I am furious at the makers of FV. They will not stand up and tell us the truth. Rather they will let babies die. Good luck with this little sweetheart.