I don't think he's afraid.
I guess he doesn't has the resources to leave tottoland to go save Pudding.
BM is down, cracker is out and smoothie and pero are missing..
Tottoland already faced an intrusion by BBP and with news of BM's defeat, the territory is more vulnerable to attacks now
So, I think Kata is guarding the tottoland and wisely so because going after pudding in a yonkou territory leaving your own territory unguarded isn't a smart choice to make