Basking is okay...sort of. If it's night, he's just warming up. Remember he's a hatchling and still learning things. This may be his attempt at thermoregulating. How much does he weigh now? If he starts losing significant weight, then you should be worried. He ate once for you so that means he has the ability to do so. Some hatchlings need to be assist fed in order to be taught to eat. If you can tell me how much he weighs, it'll be easier to figure out when the danger zone comes. But if he's a hatchling and he hasn't eaten for 3 weeks already, you may only want to extend this another week before attempting an assist feed. But remember, ASSIST FEEDING IS A LAST RESORT.