What tranny fluid did he refill it with? Do you even know what tranny you have and what fluid it takes?
I'm sure you had more than 1 quart of ATF in there when you drained it. Since you did a simple drain and didn't drop the pan, you probably lost 3-4 quarts. There's probably still more ATF in the torque converter and the filter to do too much damage.
The Vavoline MaxLife Dex/Mercon ATF fluid covers most of the e46 trannies.
You don't want to drain and refill it too quickly. Changing it frequently will shock the system and make things worst.