When Jo came, he was very angry and struggling to cope with the loss of his mother. His father Gary, was asking Michael to chose his lunch from a long recited list of frozen foods, Michael responded with a meltdown. It seemed due to the frustration and pressure of having to plan his own meal, combined with Jennifer's arrival.
When he ran upstairs, and went to his room and hid under his bed, and began crying that since his mother died at 32 years old, it seemed like "the end of the world." Jo saw Michael clearly grieving over his mom aged 32, and didn't have any outlet to express it.
Other than this meltdown, which Gary said was like nothing he had seen from Michael before, Michael was the most well-behaved boy in during in this episode. For example, when Sean went to the Naughty Circle and Sean didn't apologize twice, Michael asked Sean "Are you going show Jo-Jo a real apology?"
He was 6 years old when he was on Supernanny and is now 13 years old in 2017.