yes mate, I signed him up for it and gave him one of my old laptops
It's possible you can still do it off the firestick, depending on what means you do things by. I know that, illegally, Amazon have stopped access to Kodi as it claims it accesses personal data (well it has for me).
However, you can still do Kodi via the laptop. If it's just to watch sports there are some ext. apps through that player you can get (The Loop is pretty good for that) otherwise you would need something like an ext 'Debrid' account to watch other entertainment as well to keep the old man engaged.
'Diggz' is a decent catch all for this, but may be a touch complicated unless you show him regularly how to access. Plenty of tutorials out there on how to do it, Kinky.
Oh, some people want me to 'mind my own business', so ignore what I wrote you...