He's surprisingly chirpy for someone who just lost his father.
If you describe a person or their behaviour as chirpy, you mean they are very cheerful and lively. Hutson is a small, chirpy bloke She sounded quite chirpy, all she needs is rest. = cheerful. happy and active
characterized by liveliness and light-heartedness; "buoyant spirits"; "his quick wit and chirpy humor"; "looking bright and well and chirpy"; "a perky little widow in her 70s"