The main thing is to avoid stress. Hamsters get stressed easily and that can make them unwell. So if you have plenty of nice cosy bedding and a few hides and don't clean him out too often, and he has a good wheel and diet, that is a good start to keeping him comfortable. Little things can perk them up too. They can enjoy the occasional healthy treat - human leftovers or a tiny bit of porridge oats on a teaspoon. With human leftovers it needs to be plain cooked, no sauces or spices etc. Eg a tiny bit of chicken or meat occasionally. Or a bit of scrambled or hard boiled egg. This is also supplementing the protein they need in the first year to build strong bones and muscles.
