are you "no ME rating" or no rating at all..

Actually, I'm the instructor. My student's father bought him a 182 to
do his instrument rating in, whereupon he sold the airplane for a
profit and the instrument rating was free.

Since his father was willing to buy a twin, I suggested doing his ME
Commercial before his SE. However, his insurance agency said they
won't insure him until he has his ME, so we're considering doing a
private ME add-on, VFR only, in our flight school's Seneca, and then
go for his Commercial ME in his own airplane.

However, it makes far more sense to do everything in his own airplane,
if he can get insured.