He thinks Karen is too soft with the 4 kids. When Jo was gone he sends Joshua and Lauren in the Naughty Zone for getting out of their seat and laughing.
Jason doesn't approve of Jo, but he eventually warms up to her. He admits that everyone but him has been following Jo's advice. When he sees that it works, he commits himself to change, too.
He was 31 years old at the time and is now 43 in 2016.