I'm sorry your baby is not eating as well as he should. They can be so stubborn!
Maybe you should sit down with your brother and talk about the attention that Bobo will need while you're away. If you don't feel that he will take things seriously, please consider having someone more responsible take care of him for you, or cancel your trip.
The Nutrical, IMHO, is for use in EMERGENCY situations only. Given too much it can cause problems. It's for when they just will not eat due to illness or other factors. The best "cure" for hypoglycemia is to make sure that they are eating regularly and well. I have a recipe posted on the Health and Diet section, just do a search for hypoglycemia and you should find it. If he won't eat the dog food, you can try this, though I have to warn you that it's difficult to get them back onto the dogfood again
Keep us posted. I hope he starts eating better for you!