Is there a way to convert a binary dll file to text so the dll file can be read and understood?
If you have access to the symbols and a debugger, then yes.
However, without a symbol file for the binary, you can only extract
limited information from the binary. You might try
Spy++(SpyXX.exe), Dependency Walker (depends.exe), and/or a hex
editor. A symbol file will have the same name as the binary DLL, or
EXE and a file extension of .pdb (e.g. ntdll.dll, ntdll.pdb /
ntoskrnl.exe, ntoskrnl.pdb)