I would follow the directions Your vet has given You if you were asked to feed him through a syringe there must have been a reason for it.
If it is because he was not eating and it was just to coax him into eating again.
You can crush his biscuit and add water to it. If You have a grinder at home it may be easiest grinding the food, and than adding water to make it like syrup. Also try hand feeding him this and talking to him calmly whilst trying to fed him as it may encourage him.
If he does continue to eat this and it does work try to get him back onto normal food as soon as You can or try grinding the food less because if you keep hand feeding him and grinding it he will get use to it and he does need to work for it and get use to it for when he is older. Some dogs may become use to this type of feeding so make sure it is only for the time he is not eating.
I am currently working in a vet as a veterinarian nurse and studying and have also tried this on our own pup recently who was not eating as she was under a lot of stress in her new environment and not knowing where she was.
I hope this works for You and that he improves soon.
Best of luck
You could try putting a little chicken broth on his food.With hypoglycemia you have to make sure to keep his blood sugar up and sometimes that can be hard when they dont want to eat.There is a paste called Nutri-cal that works really well as far as keeping there energy up and calories in them and it works also for there blood sugar.You can also use Caro syrup,I have used it in the past with my babies.You can get Nutri-cal at a petstore and some vets have it.Goats milk works really well to.When i had to bottle feed that is always what i used.Well i hope that your baby gets feeling better soon.Take care and God Bless
You do need to make a followup appointment with your vet. If that's not possible over the weekend, try goat's milk. Most supermarkets carry it either in the dairy case or in cans. You may still have to resort to the syringe, but give a bottle a try. He's still young enough that he might take to a bottle.