My MIL is the queen of tiptoeing...well no let me take that back the entire family is. Wake up your son/brother is heading down the gutter again. But I gave up on that battle. It is no longer my job to convience them of his problems...and literally that's what it was. At first I was the one with all the problems....really? Really? Pretty sure I don't have a drinking problem, pretty sure I've been the parent to our son when he was out cheating/drinking, wasting his life away. Ohh I could go on.
I have tried with classes, books, etc...to get his mom to see of her enabling ways to no avail. I give up. I commend you for holding strong with your daughter. I just told someone today...regardless if someone is family if they screw up they screw up they are still held accountable. Still hold them to the same morals and values I have. Whatsmore is if Jack, my son EVER treated his wife & child the way Mark has you better believe your butt I wouldn't be tiptoeing. To each their own with their parenting, but at some point you have to think...what you're doing isn't working. But that would require the blinders to come off and some acceptancing in playing a part.