The reason I brought up and taught grammar is because I think it’s generically important and should be a priority for people interested in philosophy. It’s an intentional design decision and topic choice by me, which I would do with ~anyone. It was not a request or choice by the student, nor a customization to cover a weakness of theirs.
If you already know parts of speech, clauses/phrases, sentence diagramming, and the material in Peikoff’s grammar course, you could skip a few bits. But I think you’d still find some things you don’t know in my grammar article. And I’d still think learning grammar trees is worthwhile (those are not standard knowledge that you would already know, though some grammarians already know them), and is a good way to build up to analyzing and making trees for texts.