I highly recommend the Kwik Sew books, they have a master pattern you trace onto other paper/ vyaline, and ou can mix and match/ alter/ adjust to your hearts content.
The only issue I'd see would be that you'd need two of the books, sewing for toddlers (I'm sure your lad would fit the T1 size clothes) plus the sewing for children, as the sewing for toddlers only goes up to T4 (about 4 yrs).
The books still seem to be the same price I paid for them yonks ago, around $30 a book - from what I've seen anyway.
I've had the books for ages (over 11 yrs) and I still use them as my main source of sewing patterns for the kids, I'm really looking forward to sewing for the baby now too
