The way I see it, the letter accomplishes several goals in one fell swoop:
-H needs to calm the f*ck down! -H needs to realize that HaWho is no pushover -H needs to recognize that HaWho is entitled to her own lawyer -H needs to be slapped into reality that there are kids involved--aka get his head out from his own a@@--no telling which 'head' we're talking about here- (from what I've read so far, H has a tunnel vision on HaWho in all of his communications with her...with nary a peep of concern for the kids) -and put the brakes on this crazy-moving train a bit
I am thinking that you may have some other angle that we hadn't thought about there and I'd love to hear it, Ellie.