I am a solo hunter too most of the time but, my grandfather and brother-in-law both know exactly where my stands are. If word isn't heard from me in a while they know where to look, just in case. Take your dad to your hunting spots and show him how to get there and tell him "if I am not back by such and such come and get me" . That will ease his mind, it helped with my wife by showing grandpa and my brother-in-law.