I'll add my well wishes for your mother. I used to live in Lancaster, but not for a while now.....my memories of schnitz un knepp were mostly that it's an autumn dish, so many restaurants will have it available in the September-October-November timeframe. That would also be when the best chicken corn soup is available as well, and both of them are known to be had at firehall festivals (basically fundraisers) at that time of year. These are hearty and warming dishes that don't get ordered very often in August.
If it was me, I would check out the family-style restaurants in Lancaster here -->
click <-- and tell them your situation. I would bet that within 10 minutes, you'll find one that is willing to make it for you and even deliver it.