You can find the matching Sandals here: https://www.craftsy.com/pattern/crocheting/Accessory/TrekkersFlip-Flop-Sandals-for-Baby-Boys/24584
I had started working on this crochet pattern for boys last summer along with my girl's sun hat pattern but never quite got down to publishing it. I had lost all the written instructions and just had the hat samples left with me. Feeling lazy to rewrtite the pattern, I tried guessing the stitch counts from the finished hats but it was a total disaster! Now I know why people buy patterns and don't try to wing it by looking at the picture. The pattern which looks quite straightforward poses its own challenges when you finally sit down to write it down. I have kept the design simple to suit your little boy with just a contrasting band added.