My recipe for dealing with anger and frustration: set the kitchen timer for twenty minutes cry rant and rave and at the sound of the bell simmer down and go about business as usual.
When you see a struggle that you may be having personally put on a big screen and in a roomful of people then it makes you feel less crazy or alone because you're seeing that other people are dealing with it too. You get to see in this imaginary scenario how people might try and answer some questions or deal with some problems.
Being a father at a later age is different from when I had my other two daughters when I was in my 20s and 30s. If you're in your 60s and you're with the kid every day you're dealing with the mind of a child so it opens up that childishness in you again.