> No, he's right. One should not pin their happiness to things outside their control.

I don't think this opinion is realistic or helpful. Being fired has an important impact on your happiness and the quality of life of you and your family, specially if the next job forces your family to move.

Some people are forced into homelessness when fired. Are we supposed to pretend that losing your home does not hamper your happiness?

It's unhelpful to suggest we should not stress about things outside of our control, because we still need to deal with them.