He sold at least 2M shares between 25-30 (Lets say 55M worth):
12/31/97 9,801,552/shrs D and I
4/99 7,941,998/shrs D and I Note: he could have sold more than this(probably did -- I vaguely remember 1 transaction that was over a million shares) but the nexr sec report is 9/1/99 and he had already started buying back by then.
Anyway, you are making a huge assumption when you suppose that HUM's stock is all or even the majority of DJ's wealth. I would seriously doubt this. I just don't buy the notion that DJ estate planning is going to influence when and for what amount this company is going to be sold for. Remember, he owns less than 6% of the stock.