this subject can be deeply approached from many levels.

I may look at money or financial wealth as one of the seven masteries of life..

a great man once said "if you cant even handle your own personal finances, the mudane things of the earth, then what business do you even have contemplating greater truths"

the fact of the matter is that money should be mastered so it is there as required and then we can begin the real Work. (which to our surprise was already begun in the process of creating that forsaid money)

so the end of the story is anybody that says you can't have lots of money and be happy is speaking hogwash andits ridiculous to say that money equates happiness as these are generally measured on completely different scales, meaning they are completely neutral events that occur independently of one another.

specifically regarding your miserable friend.. maybe have him take a look at how exactly "how" he acquires his monies. Does he leave a trail of goodwill or a trail of something else (however legal it may be)

whatever trail teh peoples leave catches up eventually with them in subtle (or not) ways.