[stomachmonkey]

Just come up with a boilerplate answer every time it comes up.

"Stop, I gave my professional advice on this matter once. If you wish to continue discussing it I must advise you that the 1st hour was free, any further conversation regarding this matter will be billed at the friends and family rate of $150 an hour. Shall I start the clock?"

You may have to repeat it several times before they get it but get it they will.

I understand your concern re: the x's and kids. That's the messiest part IMHO. Can you convice your brother to put everything in trust with an independant attorney? Position it as looking out for the best interests of your nieces/nephews. You have nothing against the x's but the fact that there are 2 of them could make it messy for his children and you're sure that's not what he wants.