So as a parent, you gift the money to your children on the condition that they lend it all back to you until your death. If the children don't behave up to your expectations, you'll just spend it all on booze and hookers^w^w^w really expensive elder care and be insolvent by the time you die.
The bottom line is, if someone wants to leave a significant inheritance to their (grand)children, there's little that can be done about it with tax policies only. By the time you have plugged all the holes to prevent inheritance, you've also prevented most of the things we consider necessary for the function of a capitalist free economy.