McDavid now has 28 points in 16 games.
Assuming Oilers reach the final (and assuming no injuries) - he will play anywhere between 22 games to 26 games these playoffs.
Current PPG paced out to 22 games = 39 points, 33 assists
Current PPG paced out to 26 games = 46 points, 39 assists
Gretzky's all time records is 31 assists, and 47 points (Lemieux is #2 at 44 points, then Gretzky again at 43, 40). So the asssist record is definitely within reach, and so is the point record although that's a taller task.
A lot can happen still - including Oilers being eliminated in 2 games - but if Oilers do reach finals there's a really strong chance he could set an all-time record or two. I know Gretzky did it in less games, so on a per game basis he'd still be above (points per game, for assists per game it's actually close), but this would still be spectacular.