How should windfall gains be prudently managed to ensure long-term financial stability?

livemint.com:

One evolving trend in the wealth management industry is the fast pace at which wealth is created in India. In today’s scenario, this wealth creation is happening in the case of new-age businesses, first-generation entrepreneurs, technology entrepreneurs, senior corporate heads, and professionals and is not restricted to traditional business houses. 

This topic actually reminds me of a family in which there was a sudden wealth creation many years back, and I had the opportunity to be one of their wealth managers at that time. This case study will clearly show the importance of prudently managing the windfall gains whenever there is a sudden wealth creation.

Some 25 years back, this family received around ₹15 crore when a larger conglomerate acquired the company they owned. Now the CEO, who was 55 years of age and was earning ₹1 lakh a month, had suddenly made a windfall gain and hence decided to retire and enjoy his life. The first thing he did was to invest a portion of that surplus into the markets while he also splurged on a few amenities like buying a very lavish house, cars, and a holiday home in Shimla. He organised extravagant weddings for his two daughters after they completed their higher education. 

However, things didn't work out well for the former CEO, and he realised that if he lived beyond 70 years of age, he would not have the same financial muscle he had previously enjoyed. By the time he recognized that he had made a big blunder, it was too late, as the markets crashed; the exorbitant lifestyle was now becoming way beyond his means, and greed had slowly caught up with his daughters as they started choosing money over their father, all of which led him to depression a few years later.

As wealth managers,