it would still get burnt it doesn't instantaneously absorb it it takes time and it Samehada gets hurt by fire so there fore amaterasu would destroy even if it absorb it it would still take time and then madara can simply hit it again with amaterasu just constantly spamming it all that will happen is that it will slowly absorb the chackra while being destroyed its not going to instantaneously absorb amaterasu no way.Okay, okay.
Amaterasu is absorbed by Samehada because it is chakra.
Tsukuyomi is stopped with Samehada as well.
Madara separates Samehada from kisame yes samehada will get back to kisame but not straight away it has to get to him which takes time and 1 second in real life is like 24 hours in Tsukuyomi by the time samehada gets back to kisame , KISame is destroyed and on the floor