Mann HU718/5X is the fleece filter for '99 SL500, it's the same filter for many E class. Rockauto has it for $8.xx, it's $10.xx at Amazon, my local dealer's price is $24.99.
If he wants to change oil+filter himself, he should invest in a fluid extractor and a filter end cap then he can do it in less than 30 minutes without jack up the car.