Yes it needs more energy but do u think being negative will change something or bring her back? No...so why not to be positive instead of negative..

No one in this world can be 100% optimistic but there are few things which force u to be positive.. He has a kid...if he focus on his kid and kid's feature he can see a lot of positive things to live happy...of course few days in a year or few moments in everyday he will feel down but can recover it.