Dr. MonzerKahf, a prominent economist and counselor, demonstrates:
“Regarding distributing estates in lifetime, Muslims ought to notice the following basic principles:
1. Whatever you distribute in lifetime is considered a gift not inheritance, therefore it is better to make equal distribution to the equals;
2. One cannot forsake a right before one owns it. Therefore, parents cannot surrender their shares of inheritance should their child die before them. But only after your death any heir may surrender her/his share to another or to an outsider.
3. Remember that after the death of any Muslim, her/his estate must be distributed in accordance with the Islamic system of inheritance, this is mandatory and if you live in a country that has no Islamic inheritance system you must then prepare an appropriate document that assure this distribution.