Steve, honest to god, I fell of the bike I bought first. I got a whole five feet and then it tossed me on my fat butt. I barely missed hitting my head on the brick house on the other side of my drive way.
It did give my shoulder a terrible whack into the neighbors chimney. I hit it so hard I know it had to have moved some. I scraped my knee leaving a strawberry at least the size of a coffee cup. I tried to ride that darn bike again the next day butt that time I took it to a church parking lot. I got in the corner where there were no houses. The bike and I did not get along. I couldn't pedal the darn thing for some reason.
I was between a rock and a hard place. I knew for sure my automobile driving days were about to end. I knew I did not want to be trapped in the house totally. I knew my walking was helping, but I hated it. So what did I do? Why I bought a bigger bike of course. I bought a twenty year old huffy coaster, a true tank as bikes go.
That sucker was so big a basketball player could have ridden it. That old rusty red huffy taught me a lot about balance and a bit about freedom. I motorized it electric but I had a terrible time getting my leg over it. I was pretty shaky on it but I stayed with it.
All along I was learning more and more about bikes and how each part effected me. For instance I learned that switching out the rear wheel for the wheel of a child's 20" bike make it sooooooo much easier to get on. It also mean my feet could touch the ground easily from the seat. but of course the pedals hit the ground when I leaned into a turn.
Then I discovered that the child's bike I bought for the wheel, had a shorter crank set and was interchangeable with the huffy. And that is the basic setup I used for over a year with different bikes as I experimented.
When I built the bubba I decided to try to dropping the front fork of a twenty inch kids bike down three inches. That made it possible to fit the 26" hub motor into the front fork without having to change anything else. It is remarkable except that it is a little light in the front but still not a problem since I have my balance mojo working these days. I did have to make a seat extension so I could pedal comfortably. I haven't really checked but I bet I could buy a longer seat rod at the bike shop or on line.
On the robo tandem, I switched the front fork from the 20" bike for one from a 27" road bike. I just had it laying around and thought it looked cool. I can kid myself into thinking it looks a little chopperish. but I did put the 20" wheel back on the robo tandem bike. It now has a little bit of a rake to it.
The point is, if the bike they have isn't comfortable, just figure out why and build your own. It would be cheaper anyway.
By the way sorry about the fall. Mine hurt like ****. First I was embarrassed, then I hurt, then I got mad and refused to let that piece of crap bike beat me. So I guess I'm saying stay with it. It can only help in the end.