Do you actually have the lazarus .chm help files? My /Users/trev/lazarus-src/docs/chm directory is empty.
I moved in to the /Users/trev/lazarus-src/docs/html directory and found a script to compile a Lazarus program to generate the .chm files. The script fails with:
Error: (lazarus) invalid Lazarus directory "/Developer/lazarus/": directory not found
Error: (lazarus) Building failed: build_lcl_docs.lpi
So I opened the project in Lazarus and successfully compiled build_lcl_docs. Unfortunately though, running build_lcl_docs generates... an error:
FPDoc - Free Pascal Documentation Tool
Version 3.3.1 [2019/10/22]
(c) 2000 - 2003 Areca Systems GmbH / Sebastian Guenther, sg@freepascal.org
(c) 2005 - 2012 various FPC contributors
Exception at 000000010008796C: EInOutError:
File not found: ../../chm/rtl.xct.
10 Warnings hidden. Use --warnings to see them all.
An unhandled exception occurred at $00000001000047C4:
Exception: File not found: /Users/trev/lazarus-src/docs/html/lazutils/lazutils.xct
$00000001000047C4
$0000000100004960
1. The directory ../../chm/ does not exist.
2. The file rtl.xct dies not exist anywhere on my system (Lazarus trunk).
3. The directory /Users/trev/lazarus-src/docs/html/lazutils/ does exist but contains only:
* fpdoc.css
* inputfile.txt
Hmmmm.
BTW, LHelp opens my own .chm Windows help files without an issue.
[UPDATE]
I eventually found pre-generated help files in chm format at:
https://sourceforge.net/projects/lazarus/files/Lazarus%20Documentation/Lazarus%202.0.6/