This is certainly a tragedy and I wish my most sincere condolences to this person's friends and family.
As far as the weight of his pack goes we can only speculate (which is typically foolhardy), but here I go in an attempt to answer the aforementioned question.
My guess is that he had more gear than most of us would carry but as a result of hypothermia could not think clearly enough to utilize the life saving equipment he likely had with him.
In my experience those with extremely heavy packs are either those who bring more than what they truly need due to lack of field testing or are those who bring enough equipment to save their own life and some doubles on gear (headlamps, extra batteries, back-up snowshoes, etc). I'm certainly not saying that those who bring more than one item of various types of equipment are making a mistake but merely offering a second plausible explanation for a very heavy pack.
My intent is not to steer this thread into an "overpacking vs. underpacking" discussion, but I thought I would offer some sort of response to the previous post.
My condolences again,
Z