People like this don't understand the term 'save for a rainy day' because to them their enjoyment comes first.
The problem is there is no convincing such people, only life can teach them a lesson that's if they will ever learn.
You can only keep advising him as a friend but the rest is up to him to figure out.
Indeed, there are people who are so relaxed with either the little or the huge one they have gathered and decides to chill, consum it til it depreciates to an obvious level of decrease and conciously, just because they don't want to run a zero % that aspirations alone urges them to go back and hustle once one and relax again and chill to spend up all that accumulated again and before their realization they are up to retirement age and would end up regretting all steps of their lives where "Had I know" would never depart from their thoughts.