"no offense intended, but they'll need to look for stuff made for "clydesdale" riders....I'd suggest hard tail mountain bikes built for these riders... lots of really big men out there who ride bikes and break stuff just by the virute of their size...."

I agree. They'll need sturdier rims and components too but do the suggested bikes come with that?

Lets get these folks on a bike ASAP! It's a perfect exercise because there's no stress on the joints. Why do a low impact class to get to a low impact activity? I'd encourage them to start riding, just start slow and low mileage.

As the pounds roll off the Clydesdale bike will seem too stiff for them and they'll need to upgrade/replace. But they'll roll across that bridge when they get to it

Do they have access to a gym with a stationary bike? Again, no offense intended, I've a few extra pounds myself but after years of innactivity they'll need to get used to balance on the bike.