Ask him to help you make the list of all that needs to be done and have him help you figure out a less time-consuming way. That way you are asking for his input in solving what he doesn't know is a problem and he won't take it as a criticism he'll take it as his opinion being valued.
Remember, you can lead a horse to water but you can't make him drink, unless it's a male horse and he thinks it's his idea.
Remember, you can lead a horse to water but you can't make him drink, unless it's a male horse and he thinks it's his idea.