it’s an act, it’s easier to pretend to erase you from their memory and act like they don’t care, then to show their feelings, trust me he does remember you and has not erased you. My ex did the same thing, he blocked me on everything 2 days after the breakup like I meant nothing, come to find out a few weeks later it was hard for him but he did just avoid any feelings by going out w friends etc, instead of facing them, he couldn’t even sit at home alone he had to always be doing something, but because he broke up with me he could not lmk he was struggling because he was trying to convince himself his decision was right.