He should give it until HE is ready to be divorced, with no emotional baggage, and can move on healthy and happy. He certainly shouldn't go file just to have an effect on her.
I don't get into time with these sitches. Some sitches should be resolved by the LBS saying "SEE YA" in 5 minutes. Some could take 5 years. Time is meaningless to me in these things. But clearly he is not ready to move on, and until he is....he shouldn't. I believe that to my core even if its been 40 years.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712