Fast forward to now, and of course it doesn't fit anymore! D'oh. I knew I didn't want a repeat, but he needed something to put over his clothes for puddle stomping.
I found this adult vinyl slicker at the thrift store for $2. It has a logo of something sporty, which got mostly cut off (you can see it under his left arm in the lower right "after" pic.)
We tested it out as-is and it was quite hilarious. The hem touched the ground and he got his boot stuck in the elastic.
Here are the steps I took to reconstruct it, and it went pretty fast as it's a pattern and shape I've sewn before. I knew it wasn't going to be 100% waterproof, but I kept the hood intact, and the back is one piece, so it should do a pretty good job.
First I cut the elastic hem off so I could see the shape. Then I cut the hood off and estimated the height (removed pull cord.) I measured his arms and I was going to use the original gathered cuffs, but decided to re-sew them without elastic, so I traced a pattern piece and made them a bit roomier. The goal was to have it go over clothes, including a warm jacket if needed. Then I cut the front, including removing the zipper and the front pouch. I traced the arm holes from a pattern, and sewed it all up with a long stitch.
Someday I'll make him a nicer one that's lined and waterproof, but this is pretty good for a quick project.
We also got our Christmas tree this last weekend, and H got to help pick it out.
And he enjoyed the spiced cider.