Yeah I'm not sure about that.. I certainly wouldn't be selling my $2m+ eastern Sydney home just to blow the capital on one year of fun. Even though the home was mortgaged, he'd still have to have a good chunk of equity.
Selling it and investing to live far more modestly off of the returns, or earmarking only a portion of it for the trip, sure, I'd do that. The whole family could realistically have a year long trip for less than $40k, and could have come home to a modest, paid off home (or investments), stopped working or found less stressful jobs. Now they'll be back to square 1 again with no assets.
I think his desire for change is great and very understandable considering his role. But I would never throw away 20 years of long hard work for a single year.