I'm a big guy. I have the Big Agnes insulated aircore in the wide width. it's relatively heavy (about a kilo, 1000grams) but
is just the ticket for when I have to sleep on the ground. I believe cook mentioned others. There are options in a good backcountry capable air mattress.

As for the hammock suggestion, I too am a die hard hammocker, but the trick if you have a sore back is that some people do not want to be "bent" - with a hammock you do this by sleeping *diagonally* in the hammock. (with the hammock not strung extra tight to the trees.) Doing it this way I can comfortably sleep on my sides in the hammock, but you may wish to try before you buy. Hennesey and warbonnet make nice asymetrical ones designed to lie sideways in, or if you use the search function in this forum, search for "Test Hammock" - there is a link to risk's test hammock you can make for about 1 to 20 dollars to just try to see if it actually is comfortable or not for your husband (The other option would be
go to REI and buy a hennesey and then try it out in the yard or basement - if it's not comfortable to sleep in, return it.

I also use mine as a chair to sit in, (I actually use a homemade speer hammock, similar to the "test hammock" but with a ridgeline and bugnet added.