Never heard of either him, or his books, but the Amazon reviews are very mixed. Seems the book is more about spelling/punctuation/stylistics rather than actual grammar rules?
I would check out some of the Grammar reference books that English (as a second language) teachers use.
The TES and Teachit websites are full of resources as well, for teachers in UK schools, so should have lots of stuff you can refer to.
I like the Longman Grammar books myself; they do elementary, intermediate and upper intermediate etc. Obviously, they are for an ESL scenario, but the explanations are clear and there are exercises too.
Oxford Grammar Reference is a weighty tome, no exercises though.