I don't have experience with the plant but have experienced Pittsburgh winters. I think they are like zone 5/6 but it's been a while since I lived there. If the holly is good for zone 6 and she has a sheltered spot it might be good to go.

I love YOUR city/state...and for years my daughter has lived there. She moved home in January and in early Spring kept telling me how dismal the yard was...it was all just brown. I said...WAIT! I think she did not quite get perennials...she expected to wake up one morning in Spring and find loads of bloom. Come May she was feeling more like Spring in Atlanta I guess. She loves Atlanta too and misses it sorely.

While not from the Pittsburgh area (we live in southcentral PA) I do have an oakleaf holly. Mine had winterburn this last year and lost most of its leaves. I am happy to report, however, that it has recovered quite nicely so far this year.

Seems even the hardiest of hollies got winterburned this past season. I have several oakleaf in my yard but I too am a bit further south.

Zone: Northern Virginia-
I have 3- 8ft. Oak Leaf hollies planted in large cedar containers on my terrace. They produced a small crop of berries the 1st year, but have not seen any berries in 3 years? I was told they are hermaphroditic and did not need male and female trees to produce berries.
I spray them all with Wilt Proof just before the first frost-usually late Oct. here. This has greatly reduced the winter damage I experienced the first year. I prune and fertilize with osmacote for trees and shrubs(Late April or May) What could be the problem?