Many parents want to teach their children English very early. Sadly in some parts of the world it is hard to access Youtube and other websites.
I have found some sites that teach using free materials, if there are other better sources I can give parents purely as homework or review please share.
Free books (PDF): https://freekidsbooks.org
Lessons (better with a teacher teaching): https://learnenglishkids.britishcouncil.org
Last option: Teacher made review videos.
(If youtube is not an option but kids like videos, create a cute, fun, interactive video reviewing the lesson)
Parents: These are some websites you can use to help your child practice English. Or you can ask a teacher to help using these sites!