Boys learn so differently to girls that a “school learning at home” approach is probably not the best way to go about it - especially if he’s like my two rambunctious boys, lol. This article does a great job of summarizing the differences between boy and girl learning! https://blog.traillifeusa.com/what-a-boy-needs?hs_amp=true
Kindergarten prep is more about life skills than specific knowledge. Playing Simon says, practicing putting on a coat and shoes, washing hands with soap, opening food from a lunchbox... You can have days where you play "school" where you do storytime on a rug, look at a calendar and sing days of the week or months of the year, have recess and then art (make sure to have him clean up his own paints, paper, glue, scissors, etc). He will have a great time and be ready for the fall.
It's pretty normal. I used to be a preschool teacher. I started my little girl early and any time she wanted to help I let her so she's my little helper now that she's 3. We also do homeschool busy books that actually keep her a bit more focused we started just working on one page a day and now we work through several pages. And it's not everyday either.