He probably understands more than he can speak just by having been around someone who speaks English.
My partner speaks to me in Spanish and I reply in English a lot. I can understand more than I can speak.
(We also speak in English a lot too as he’s bilingual)
When I had this discussion with my OH about it he was surprised I didn’t give my mum money every month lol It’s cultural - for him where he’s from they simply dont have not a lot of money. Everybody pools together…as the oldest son there is an expectation on him to give money - his mum needs it. They don’t have a lot. Also there’s no pensions. It’s not a thing that exist where he’s from. As he put it- u don’t help the elders they die. My grandad also sent money back to barbados to his mum until the day she died for the exact same reason