I have blocked H's email address. I had blocked OW's a couple of years ago after she sent email to me bawling me out for not "dealing with the break-up of my marriage". Now they are both on the blocked list. Kind of ironic, isn't it.
Everything happens for a reason, maybe Dad needs to find that it isn't better out there, he needs to realize how good he had it here. Maybe he will find God and that is the most important thing when he finds Him he will know he is supposed to come home.