For many years, it was legal to indicate your donation by checking a box on the back of your drivers license. If you did that before September 1997, the instruction is still legal. If you want to indicate your donation after September 1997, you have to use one of the three methods I just mentioned. Your drivers license is no longer adequate. While all three of the methods are legal, the method you select must be sensitive to the speed requirements of donation.
Any lengthy delay makes an organ donation impossible.
Hence, you should avoid using your Last Will and Testament because it could be days before anyone reads it. In the interest of speed, it is much better for you to carry a donor card. Your card or written declaration must be signed by you and must be witnessed by two people. If it is, then your wish to donate must be honored even though your son objects. Assuring yourself that your wish will be followed should only be your first step.