All of the Dr. Suess books that were published before he died. (His wife “found” some liberal crap “in some bottom drawers” after he died.)
All of those fun rhymes make ‘em giggle.
...and then talk to him a lot—looking him in the eye and using his name.
And hug him close because he’s going to grow up so horribly quickly that it will hurt your heart.
A coworker of mine had mentioned that Seuss had written some political commentaries when he was still alive that were very bitter and VERY liberal. I’m not sure if that’s what you are referring to, but I did remember hearing that.