When I was there last year, I linked it to myself and it worked for everyone in my party. Just be sure that your group is created in myDisneyExperience. My husband didn't have his own account, so everyone was within my account. I don't know if that makes a difference.
Memory Maker can be very worth it depending on how you use it. We got all of our ride photos (which we love to see), and we did a lot of character meals, so we got all of those photos. If you see a lot of characters and actually take the time at some point in your trip to get pictures at the major parts of the parks (Castle, Hat, etc), then you will have a ton.
However, I feel that the package was worth it for one reason, and I would buy it again for this: Jedi Training.
Not only did I get a bunch of great action shots of my son, but you also get borders. He thinks the pictures of him with the Star Wars borders are so cool. You can save your pictures in different sizes and with different borders, so it multiplies the number that you get, but you have to do it and then download everything before your pictures expire on the website. Pictures are downloadable and a CD is extra now.
I think the best thing for your hubbie to feel the worth is to be sure make a book after you get home. You can use any service like shutterfly or Costco, so it's not that expensive, and you get a great memory piece your hubbie and the kids can all tangibly hold. Also, this allows you to put personal photos into the book as well.
Belle was also fun, especially if your child participates in the show. It allowed me to see all of the moments with my own eyes and enjoy them instead of constantly being behind a camera. (But if a shot is REALLY important to you, get it with your own camera too, because sometimes lighting/angles/eyes closed/any imperfections come in the Memory Maker photos, and you don't want to be mad that you don't have a picture of that special moment.