It is mentioned ( albeit vaguely ) in Gillette’s profile that his return to duty after the hurricane is counted as miraculous. This will be linked in to provide the context that Gillette himself is unaware of.

Daniel’s survival was touch and go for nearly two months after the Dauntless was destroyed off the coast of Tripoli. Though he was stabilized by a local surgeon, he needed to be transported and tended to by a specialist back in England. It was predicted then that if he lived, he may likely wish he had died.

For six months, Daniel could not walk and was in fact near to that point of depression and misery where he did indeed resent his survival and the efforts taken to preserve his existence when he saw so little to do with it. Eventually his father managed to convince him he could continue to be of service from a clerical standpoint – and though he was bitter and tired, Daniel applied himself to the task all the same.

His mother, however, could see the life draining away from him. She knew well what the loss of his legs meant for Daniel – and seeing as they were not removed so much as simply not responding, she believed she knew a way to return the spirit to her son if she played her cards right.

Unbeknownst to Daniel, his mother made a deal with a witch known both for her miracles and her curses. Everything comes with a price, and what Sarah Gillette paid is not something that need be discussed – what is best understood and addressed is the results of the bargain she struck.

Eighteen months after the hurricane, Daniel was encouraged to try to stand one more time by his mother – this success shocked him, and lead to him undergoing a recovery period as he regained his strength and his trust in his ability to walk again. Less than seven months later, he was back in service to the Navy and convinced his recovery was no more than luck and a blessing unexpected.

Though he has had little reason to wonder about it, despite the damages his body took, he has suffered no ill effects. His immune system, in fact, is stronger than it has ever been. As part of the bargain, the witch strengthened his abilities to withstand infection – which in essence, includes such small irritations as colds and flus.

However, she could not repair everything – not without it being suspicious, and drawing attention to the Gillette family in an unfavorable manner. Thus, the pains and swellings he suffers from are the price he pays, for a deal he doesn’t even know was made. Nevertheless, were he to learn of it chances are he would not be alarmed; having personally fought undead pirates, being healed by a witch seems a rather minor bit of magic, all things told.