Holliday has one thing going for him - his dad was a good hitter for a long time.
Not that it guarantees anything, it's more that his dad knows what it takes to succeed as a big league hitter, and he's probably more likely to listen to his dad. Even if Sox coaching inevitably fails him, he has options.
In other words, he might be more immune than most to the typical shitty coaching the Sox seem to provide hitters.