He was sitting in his son's backyard, ever since his son had grown up and married Astrid, he had been somewhat lonely, at least he had his wife back. But he had been asked to watch the kids, so that's what he was doing. He was watching Nuffink, Hiccup's son, Zephyr, Hiccup's daughter, and you.

Hiccup and Astrid were out, having just gotten their dragons back, they enjoyed going on long flights together. It was how they spent time together. And Stoick was more than happy to watch his grandbabies.