My dad sends pictures of flowers with Bible verses or similar platitudes on them. And he does it to everyone constantly even at weird hours and even if they never respond. Most of us don’t have him blocked. I have him blocked because he crossed some major boundaries and I no longer trust him to make safe decisions around me.

So if this is the worst of it then, no, you probably shouldn’t block him. Without further context, this is annoying at worst. Also, by “block him” do you mean going no/low contact or do you mean literally just blocking his phone number and interacting with him as normal otherwise?