From what I've gathered this is where he was located. Roughly ~25ft ASL. Looks like a solid structure but appears like its only 1 story tall. He's on this persons search listed as not found but who knows who reported that.
https://docs.google.com/document/d/1M9wVx_Krgzb2cycTOGF4ZsS5JDrvRGwggCblUGtq6II/mobilebasic
"Morgerman, Josh (Central Abaco Primary School, Marsh Harbour, @iCyclone)"
I'd take it with a grain of salt for now. Josh knows what he is doing and like you said in previous extreme storms he's gone days without contact.