This is really good to know! It might be your husband doesn't understand that there's a big difference between amusement park roller coasters and
Disney "roller coasters". Parks like Six Flags, Cedar Point and Kings Dominion have the scary kind of roller coasters: super fast with steep drops and flips that leave you gasping for breath. Roller coasters like that are designed for thrill-seekers and adrenaline junkies.
At Disney, their "roller coasters" are
slower, the hills are
much smaller (think dips more than real drops), and the ride is equally about the visual experience as it is the sensation. Disney rides are designed with children in mind, well, children tall enough to ride. Disney didn't want to make scary rides because that's not what Disney parks are about. They are here to bring us amazing experiences.
The following 'coasters' are not aggressive rides. I won't go into Screamin' because that's the only traditional coaster in the parks. The rest qualify as Junior Coasters which don't have the height and drop issues typical of real coasters.
[Roller coaster scale: 1 being a mild ride that resembles a coaster. 10 being a hyper coaster that pulls the blood out of your brain and occasionally causes blackouts.]
Space Mountain, 1-10 on a roller coaster scale, would be about a 4 if you only consider how the turns and dips makes your body feel. The real thrills are visual and come from riding in the dark with blaring music and stars all around.
Space has no real drops; it goes up a large incline then gradually descends for the remainder of the ride (with twists, turns and dips along the way). Tummy-wise, there are a few spots where it feels similar to going up high on swings. Here's a model of Space. You can see that there are no big drops anywhere.
Maximum speed: 35 mph.
Big Thunder Mountain Railroad would get a thrill rating of 3.5 because it doesn't have any real coaster drops or high speeds or even scary heights. BTMRR is all about the scenery and Disney magic. Caves, waterfalls, "dangerous" mines, animals; that's what makes this ride so neat! It contains gradual descents of turns and dips instead of any one large scary drop.
Maximum speed: 35 MPH.
Matterhorn. Bumpy and uncomfortable with lots of turns and great scenery. Gradual descent. A few tiny dips that even small children love. Coaster rating: 2.5 and would fit nicely in Planet Snoopy if the ride were smoother and lost the Yeti.
Maximum speed: 27 MPH. This picture shows the one straight incline, then the slalom curves downward. At no point do get a 'top of the hill' feel like that on roller coasters. The ride travels through caves so it ends up feeling like a zany ride. It's very fun!