Its a generalization.
At 165 lbs, I would say you should be looking more for a 176cm-182, depending on the flex of the ski.
For a stiffer ski, like the PE, Karma, or Ghetto, a mid 170 would be best. However, for a softer ski, such as t-halls invaders, or foils, look into a larger length.
For the most part, height and weight go hand in hand. Typically, you want a ski that is within 5cm below or above your own height. Some like longer, some like shorter. Its all preference, and from the looks of it, he doesnt seem to have one.
With my most sincere regards,
Golden Wheelchair Nominee- September 21-28