"Money doesn't guarantee happiness." - but the absence of this will certainly guarantee unhappiness. 
We don't know the true reasons that pushed this person to such a tragic step and therefore, it is impossible to objectively assess what happened from the position of happiness received (or not received) from money.
Who told you that billions will provide you with peace and happiness? Money is a means of exchanging material goods and certainly not a tool for acquiring spiritual benefits. Everything falls into place if you understand the purpose of this or that.
If money could guarantee someone peace of mind, then the man in person would've spent half of what he's acquired to find peace but what we was going through was beyond his wealth, and he's a prove that one can have all the billions and still not get peace or happiness. I might be wrong though but what's your opinion?
.We don't know the true reasons that pushed this person to such a tragic step and therefore, it is impossible to objectively assess what happened from the position of happiness received (or not received) from money.
Who told you that billions will provide you with peace and happiness? Money is a means of exchanging material goods and certainly not a tool for acquiring spiritual benefits. Everything falls into place if you understand the purpose of this or that.