I think that Ben dies the way it's reported and doesn't appear after. However, I wonder if something happens between getting his and Rey's Force harvested and the moment when he dies that hasn't leaked yet. Because, right now, we have the following situation:
Palaptine taunts Rey that she's alone with him unlike Luke who had his father by his side
Ben shows up echoing "You are not alone" from TLJ
KoR stop him, they fight
Since Ben showed up unarmed (he tossed his "evil" saber previously) he has difficulty dodging KoR weapons
Rey senses that she isn't alone and sends him Anakin's saber via their Force Bond
Ben dispatches KoR with Anakin's saber
Rey dispatches Palpatine's guards with Leia's saber
Ben joins Rey before Palpatine
So unless Ben gives Rey the Anakin saber immediately, when Palaptine starts to harvest the Force from them, Rey has only Leia's saber and Ben has only Anakin's saber.
After Ben dies, Rey uses both sabers to deflect Palpatine's force lightning and make him explode.
How did Rey get Anakin saber?
IMO, there are 2 possibilities. One, emotional, is that Ben gives it to her saying something along the lines that his family legacy is hers now, basically passes the Skywalker torch. That would go back to Rey, Rey Skywalker. He probably does something that prompts Palaptine to zap him. The other, no emotional "passing of the torch", but he is zapped, the saber falls from his hand and Rey picks it up after the connection with the old Jedi energize her. Rey, Rey Skywalker line has nothing to do with Ben.
Now, if this was Peter Jackson circa LOTR, I wouldn't doubt that the first option was the right one. However, this is JJ"Leia snubs Chewie to hug Rey" Abrams. He is pretty tone deaf so to him, mystery about whether Ben died and where he is would be more important than give (temporary) closure that resonates emotionally. So I could see "dry death" misstep here.