What a perfect excuse to try out the pants pattern from Hammer & Thread! I found it a few weeks ago and have been meaning to try sizing it down for 5. Mostly, I just made it shorter. I'm well aware that my little dude is a bit of a tank.
Their pattern is pretty basic, but it's nice and high in the back and it's designed to be made from a Tshirt! Who doesn't love a good Tshirt repurpose?