Iʻm sorry that your grandfather died. 😭 I know that moving on is a hard thing to do (My cat and my great grandmother died this year.). Chadwick Boseman was a great actor. What you said, "Death happens, we deal with it." is true but some people really liked this actor and it is hard to move on from his death, so they might take your comment the wrong way.
Guys you have to remember a few thing: He was a fighter and fought cancer until the cancer was to powerful. He never gave up and wanted to have a happy normal celebreity life. And this wouldnt be the last time we see him! When we're all going to where he is, we will see him again!