Trafalgar D. Water Law/Abilities and Powers

Now, Law is the “Surgeon of Death” and his devilfruit is known to be able to cure many diseases, and perform surgeries right? So, is the theory that Law could cure people with Smile Fruits true, or just something to get views?

We've all seen Law's ability to cut people in half, but in the end the people he cut in half are still alive in the room, so how does he kill people with his fruit?

On the fandom it says that the effects will linger after the room is down, so does he merely render his opponents unable to move or something?