Long-term pump user here.
They do work, but aren't for everyone, and you don't really know how it will work for you until you try it. As with most things, you need some practice to get the best results.
I started with a cheap manual pump from an adult store. The constriction rings (really sleeves) provided were pathetic, so I substituted office rubber bands. My plan was to try it for a bit, see how it worked out, and then maybe get a better one. However, a few running repairs later, the cheapie is still going strong, so this cheapskate is going for full value
I suggest that hubby start daily pumping solo for the exercise, not expecting great things at first. Gradually pump to full size, then add the constriction rings. There is more practice needed here to get the amount of constriction right, again best done solo.
Then he can unleash the beast on you
As far you are concerned, you may notice a difference in size. I am a little wider than before, as skin puffs up that didn't before. My wife does not notice the constriction rings at all. But as always, your mileage may vary. Good luck.