[souffle]

It is very good that your daughter is so alert to changes in behavior and to the moods of her furry friends and shows such concern. I think she would make a wonderful hamster mummy and I would encourage her to try again, when she feels the time is right, with a hamster from a breeder.
If your hammy is glossy and feels nice and solid and is pooing and weeing OK and drinking and eating well he is likely just up and about when you are all asleep! Maybe an idea to check his teeth and make sure they are growing straight and not curving and overgrown making it hard for him to eat. Offer some special treats like a bit of porridge or a little bit of chicken, cooked pasta or tofu and keep handling him and giving him attention.