Last year (or previous one, I don't remember), Marco Cantù published the updated release of the "official" Delphi's Object Pascal Style Guide. A good start for a lot of coding choices when you have no rules and are not alone on a project.
It's online, you can read it and pick some pages for your colleagues and boss.
On the Resources / White papers page of Embarcadero website you have a lot of ebooks and books. One of them is a bible for Delphi Object Pascal developers : Object Pascal Handbook Delphi 11 Alexandria Edition
You can also read Code Faster in Delphi to have a lot of coding tips.
Put them on the Windows desktop of your colleagues, they must read books about coding and good practices !