That is where the irony of the film comes off, in terms of the language it employs - where he tries desperately to be a 'TV Dad,' to give advice and it's so pat it becomes ridiculous.
Keeping score of old scores and scars, getting even and one-upping, always makes you less than you are.
At certain historic moments, grandparents took on childrearing responsibilities. In many cultures, they still do. Chinese grandparents who are able to retire at 55 are seen all over Beijing bouncing grandbabies. In the United States, we can't afford to retire at 55.