And how many fucks did Kaido give since then? Did he ever reference the scar? The wound? Did he ever ask where Zoro is?
He is interested in Luffy
He is interested in Luffy
Ok if this sounds logical to you. He is doing better now, but let's wait before judging.
And Kaido can't too casually bring up Zoro while he is fighting someone else, he needs to stay focused on his opponent. That's obvious and straightforward.