Hmm,... good *question! And I appreciate *its logic ... given that you're already settled under the 'Old Rules' and have since become a British citizen.
But due to your son - or daughter - being a new entrant he/she will be applying under the Updated Rules ... which, in turn, suggests to me, that his/her sponsor may well be liable for the health surcharge on your child's behalf. Of course ...... I could (hopefully) prove to be wrong.
However, I'm [fairly] sure it'll be perfectly in order for your husband to act as sponsor without any problem(s).![]()