"Her husband is quite unhelpful" and "Her husband is quite helpless" are both correct English. The meanings are different. "helpless" means that he is incapable of doing things for himself (e.g. he is severly disabled, or perhaps just very disorganised and unworldly). "unhelpful" means that he doesn't provide any help to other people, but with no connotations that he is incapable of doing so. With