Well as a sccm i dont see too many nervous passengers these days. I think this is mainly because people dont tell me they're nervous. I've had to ask people if they are ok because they look very nervous. I personally think knowledge of the situation is key. I always try to find out what part of flying a person doesn't like. Is it because its a closed space? no control? height? Virgin atlantic do a one day fear of flying course which ends with an actual 30 mins flight. Whenever i have nervous passengers i request they be preboarded because once they see myself and my crew and the flightdeck crew and realise that we are well trained professionals and are here to help it relaxs them and i generally have a bit of banter and chat about their holiday and their plans and i just get the crew to keep an eye on them and not to make a big deal of the situation in front of the other passengers.
Ask to be pre-boarded if you'd like to speak to the crew or need extra time. Viking work with sunwing airlines of canada so you might have mix of uk/canadian crew and they are a great bunch generally.
Just plan ahead. Get to the airport early and get seats together. Explain that your husband is nervous and deal with one step at a time and you'll be on holiday in no time.