We got the dining package 11/11, and arrived 45 minutes before parade start with more than half of the guests for the reserved area already in line ahead of us. The only bench in the reserved area was the round bench that can seat about 4 people, but not all facing forward. I hesitated a moment (pretty much the 2 seconds it took to realize there was an open spot) and missed getting to sit by someone running in after me. There was no way I could sit on the ground, which the first 3 rows of people did, so I stepped back and offered to let some children who arrived after us sit/stand in front of me (children can have a hard time staying seated — they tend to pop up when excited, but I knew I wouldn’t mind). I did have to stand for the rest of the time we waited for the parade, as well as the entire parade. I had a hard time, for sure.
There’s absolutely no guarantee that your husband will be able to sit on the bench in the reserved area. If he can sit on the ground you’ll be fine with the dining package as long as you arrive early enough.
Disney doesn’t do well accommodating guests who have difficulty standing for long periods of time. If I were you I would plan on watching the second parade and find a spot closer to IASW — you’ll still have to spend some time waiting if you want to claim a bench, but it shouldn’t be as bad as first parade (because first parade starts at IASW, and second parade ends at IASW). Or you could rent a wheelchair and use it when needed, such as for parade viewing. There are parade viewing areas cordoned off for guests in wheel chairs and ECVs. I really hate that DIsney’s answer is to tell you to rent a wheelchair or ECV, as for many of us we want to avoid using a wheelchair if we can, even if it slows us down not to use it.