What could be the reason for his return and what can be done to manage such situation?
We don't know for sure why he returned to gambling, as there are many reasons people use to return to gambling. however, if the person knows how to control himself, then he should not return to gambling once he has committed to not touching it, because the most important thing in keeping yourself from returning to gambling after quitting is discipline and consistency in the commitment that has been made, since many people can stop temporarily but without strong self-control they are easily tempted to return.