Should I give him advice on how to manage his gambling activities or I just let him since he is just enjoying his senior years and doing things that he missed doing when he was still young? and what's the right approach, we all know senior citizens are sensitive to criticism.
Its not about telling him to stop is a good thing or let him is a bad thing for you as his friendly neighboor.
You must know his background first, lets say he gamble $100 daily while he has $1M in his bank account or his sons send him $10k monthly.
It will be useless and after that he will keep the distance from you.
Different story when he cant pay the bills, food and he is poor.
That is the time for you as a friendly neighboorhood coin-investorman telling him to stop and yes with a soft approach.