Would you care if he sold it to a different person who was looking for an investment but did not do Aikido? How about a male kyu student?
The idea of selling the dojo to a male kyu student seems equally problematic. Don't think I'd care much about an "investor" who did not practice aikido, or didn't practice in that dojo. Husbands and wives generally have joint finances anyways. I'm not sure I care that much, since I don't practice there anymore, but other threads have been running along the conflict-of-interest vein, was kindof going with that. This could start a debate about what your fees are for,teaching or facilities! Is it volunteer work?