what tools have you tried?
are you using a pincher type tool where it grabs from only 2 sides, or a circular filter wrench that distributes the force around the whole thing?
obviously the mechanic knows what he's doing... but the thing needs to come off one way or another, so if it snaps it snaps. but jeez the bloody thing must be on there very tight!
another thing you can try is to spray some wd40 or lanolin around the rim and try to get the rubber to absorb it a little overnight. the main thing is to not damage the block though, because then you'll have issues with leaks later on because the new filter doesnt seal properly.
if that doesnt work, clean the filter up as much as possible with acetone... completely remove greese/oil/grime/ and then start wrapping the sucker in gaffer tape (not the plain plastic type duct tape, the material one that you need to scissors to cut) .... round and round.... nice and tight. keep wrapping until the whole filter is covered by a few layers. this will do 3 things.... protect the filter, give it a little more rigidity, and give you some more purchase to grip onto the filter good and hard with the wrench (kinda like using a teatowel to open a jar). then, position the wrench down as close as possible to the gasket (putting it up top near the knobs will only help the sucker twist and bend due to the torsional forces. the lip of the filter is quite thick... if you dont give the filter any room to twist on itself then all the better. can you get two wrenches on it? that way it spreads the force a little if you need to use a hammer on the handles?
the suckers gotta come off mate, one way or another!