I would check explicitly with the tour operator about the ability to accommodate an
ecv.
Is the friend capable of climbing stairs/getting into a full-size van? Lifts in some hotels can be much smaller than what is normal in the US, and there are often some stair or steps in halls that limit where wheels can go, or at least the ease at which one can get there.
Hotel rooms are often much smaller. Having a place to park/charge the ecv is a consideration