Been talking to real nice guy (37) who grew up, raised and lived in UK, met him in an dating but why his English is really bad. Are there really native English people who are poor in English grammar? Or is it because he is a cat fish?

I’m not really good in English but at least I know how to use basic English words. He would text me like; “I hope you don’t mine”, (he meant mind) She wouldn’t EXCEPT my children (he meant accept) or I want to go to the mounting (he meant mountain) and and is there even a word tought???? , he texted me:” My boss tought me a lot of things, (maybe he meant taught)? That’s why I suspect that he is a cat fish. I asked for his IG but the profile was just relatively new, just set up May this year. He got only 10 followers and mostly are foreign girls. But he is just an average looking man and a guy who is still finishing his college degree. He is not rich, he is just a normal guy with a normal job, studying. Just want to know if there are really native English people who suck in their native language? Thank you!