...to your children (and not you) - is there anything you would want to say/do about it?
Apart from the obvious THANK YOU 
I have some concerns about the children inheriting large amounts of money without any regulation from dh and I. Dh and I have a friend who inherited £20,000 aged 19yrs. By 20yrs old it was all gone. This is a lot more money than that.
With any luck this won't be for at least 20yrs (dc will be in their late 20s).
The family member in question has asked for our input btw, not being a money grubbing death watcher.
It goes without saying we'd like to keep this family member around for as long as possible. They are fab.