I was tempted to say it's "Will" or "William" ... 😛
Anyway, William comes from the Old German word meaning helmet or protection. Not sure if there is a Spanish version of it.
BTW, babelfish translates this to casco or protección. 😉
Those two (William and Henry) are the ones that most people normally ask together. Maybe there is a chance he needs both. I know, still random, but then came to my mind.