Some people call the little Express models "sticks", so assuming your father has an actual stick that plugs into the TV without the need for an HDMI cable, only Roku voice remotes will work with it. Either of the two currently available will work. You can find them at Best Buy, Target, and probably Walmart, or order from Roku.
https://www.roku.com/products/accessories
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.
