I'm 5'9 155 lbs and ride a 152 and feel like i could even go shorter and be fine if i wanted to. a 153 isn't going to be unrideable.
And I wasn't saying that shorter boards have more grip, I know they have less. I was saying camber boards have more grip than RC boards and therefore if he's going to go shorter he should get a camber. Either that or invest in a specialized board for going through ice like the magnetraction on lib tech and gnu boards.