That used to be the case. Now plenty of folks are being detained -
Your call obviously, but I wouldn't be risking it personally given Ghana is on the list of banned countries. It would be awful if he got all the way to the end, had his application refused because of that policy, and then had a ban to overcome because he'd overstayed. As he can't get a visa anyway at the moment, I'd be making sure he left on time, and then going through the safer consular processing route (hoping that by the time he gets to the interview stage, the ban has been lifted).
But it will depend on your tolerance for risk and your circumstances. Hopefully you have a water tight case if you do decide to try AoS.
Best of luck.