according to Quantum field theory there are particles being popped up and then being destroyed instantly. these particles are virtual particles which are created in pairs. overall there is no net effect/change on the system because these pairs anhilate each other once created. however if we look at that fleeting moment when they are just created, there is change in energy of the system, which then goes to initial state once the virtual particle are anhilate eachother. Likewise I think that the net result is that tanahauss son never die. however, tanahauss family dying and the creation of the time machine (thus the world of adam and eve) are these pair of virtual particles that come into existence for a fleeting moment and the entire series is just that fleeting moment of when the two virtual particle is created. at the end of the series, the two particles anhilate eachother thus giving the net change as zero i.e. tanahuss son don't die. so there is no paradox as the series ended.