Father want's to give up paternal rights to "his" child. He will be 10 in a few months. How do we let our son know this?

So some background. He has not seen his son in over 3 years or even called about him. Not had any contact, no birthday cards, christmas cards, etc.Last night out of the blue my wife got a text asking if she could talk. Long story short he wants to give up his paternal rights. I will of course adopt.Should note the last time he saw his father was Christmas Day 2018 for a few hours. Before that was probably sometime in January. He was him for about 10 hours in 2015.Our son has not asked about his father in years. When he used to go to his place for visits on the weekend he was not too thrilled about having to go and we had to psych him up so that he wasn't crying when it was time to go.The question here is how do we approach this with our son? Even though he doesn't seem to acknowledge his father I would assume act of his father actively giving him away would be pretty crushing to him. I suspect he already knows that his father doesn't really want him based on the no interaction thing.Our son has already said that he wished he had the same last name as his mom, dad (that's me!), and younger brother so we thought we may approach it from that angle. What say you reddit? via /r/Parenting https://ift.tt/2k2SepE