Sorry, no matter how many times you say it doesn't change my opinion. We don't know because he never told us.
He also said in the video they had to pick the right director and the right producer and it turns out they are the ones who decided not to recast. lol
If recasting was soo important to Chadwick Boseman you would think he would tell someone involved he was sick. But he didn't because he thought HE would get better in order to continue. He had an opportunity to let whoever know he might not be around for a sequel and didn’t.