Hi
Welcome to the MedHelp forum!
If a child is really huge for age then pituitary function especially growth hormone should be assessed. You must get your grandson assessed by an endocrine specialist. Swelling of feet too should not be ignored as it can be due to conditions of heart, kidney, liver or low protein or severe anemia. Please consult his PCP for primary examination to rule out all these conditions followed by proper referral.
Hope this helps. Please let me know if there is any thing else and do keep me posted. Take care!
The only thing i can say is investigate his pituitary gland it is what secretes growth hormone.
next time you go to the dr. ask about diabetes and ask about congestive heart failure.. jus sum advice.
exactly how big is he? weight and height...does he feed on his bottle without turning colors? has his urine changed in any way since the urine tests? ever been told he has a heart murmur? any new detergents or foods introduced into his diet recently? If his feet stay swollen i would take him in... Hes not old enough to have injured them from walking...