I don't ride TSMM because it makes me motion sick. I get motion sick EVERYWHERE, on everything. I can't ride the tram from the parking lot or take a bus without getting motion sick. I take one Bonine every morning before heading to the parks, and there are still things I can't ride (teacups, astro-orbiter, barnstormer, star tours, mission space, etc). Other things make me queasy for a bit, like BTMRR or Buzz Lightyear. TSMM is one of these. I get motion sick as the vehicle whips around the corner, and it lingers as a headache and queasiness for about an hour
and this is WITH motion sickness meds. However, it's not severe. I have ridden TSMM twice and choose to no longer ride it, especially now as with tiering at HS, I can let DD use her FP+ for TSMM and mine for RnRC (another that I don't ride!).
OP, if it's really important to your DH to ride TSMM, if he takes Bonine/dramamine and doesn't mind a little residual discomfort, he should be OK. (this from the girl who can get motion sick in a bathtub!)