Kate Middleton, who is currently battling cancer, is impressed by husband Prince William as he helps out their kids, Prince George, Princess Charlotte and Prince Louis, in addition to tackling his royal duties while she’s recovering. “He’s shouldered a lot of the responsibilities, and, what’s more, he seems to be having fun doing it. Kate has seen the change, and she’s genuinely touched by all that he’s doing, not just for her, but for the children,” a source shared. “They remember their vows they said at their wedding,” an insider said of the special moment. “It forced her and William to take…