The wheels will fit fine subject to the following caveats.
The tire size is wrong for the W210 chassis, use proper tire sizes.
The more complicating factor is that you've only included the front wheel spec. R170/171 came with staggered wheels, so the rear is probably a 7.5" with a different offset. (The wheels should still fit fine, however.)
That means your buddy must be uber-cautious about ensuring that the staggered tires he selects are of the proper size to maintain a very close OD differential, and if the wagon is a 4matic, it's got to be nearly identical.
And, of course, this does away with the possibility of rotating them, so his tire life will suffer. (Industry standard is not to mount the same size tire on staggered wheels, but he might find a shop willing to do that.)
Personally, that's too many sacrifices for a set of wheels. I'd instead choose something better suited to the W210 wagon.
Good luck.