In Andrew Clements' book Frindle, what does Nick's dad want him to do with regard to using his word?

In Frindle by Andrew Clements, Nick
makes up a new word, "frindle" to take his language arts teacher at her word. Mrs.
Granger told the students that by using a word, each person made a decision about what
words would be used in the dictionary and in speaking.

Once
Nick introduces his new word, all of his friend begin to use it. It annoys Mrs. Granger
and many, many students get detentions and writing assignments for using the word when
they had been asked not to. Eventually, the principal, Mrs. Chatham, visits the Allen
family at home one night. She tells Nick's parents what has been happening and lays the
blame at Nick's door. Surprisingly, Nick's mom doesn't think that using the word is that
big a deal. The problem isn't really resolved, and Nick believes that in some ways Mrs.
Granger enjoys their little battle over the use of words (which she absolutely loves—the
words, that is).

When Mrs. Chatham has left, Nick's father
speaks to Nick. Because there has been a fuss, his father thinks Nick should
stop:

"Well,"
said Nick's dad, "if it gets everyone upset and makes the principal come talk to your
mother and me, then it must not be fun for everybody, is it? And I think you should just
tell all your friends to knock it off, right now...I mean,
tomorrow."

So while Nick's
mom sees no harm in using the word, Nick's dad believes that the disruption it causes at
school makes using the word a bad idea.