Tips for teaching my adhd friend a foreign language?

I'm trying to teach my online best friend my first language (Italian), but he has adhd and dyslexia and is struggling a lot.

He's a really smart guy, he's into coding, he's developing an app, he loves studying...but language learning is definitely not his thing and I don't know what else to try since there's nothing specific on the topic online.

He was not taught in school how the basics of grammar work (subject, verb, tenses...) so I found out teaching him grammar is out of the question.

He's been learning with Duolingo, it's going well just too slow

We tried a textbook. NOPE.

I tried teaching him some simple sentences like how to use prepositions of space but it took us sooo long and it was overwhelming for him

We tried following a language learning podcast together and repeating everything it was teaching (Coffee Break Italian), again too overwhelming for him because of the huge amount of information to remember

We tried yesterday some very simple A1/A2 level grammar exercises, it went well in the parts he already knew, but I struggled teaching him new things since he doesn't know grammar terminology

What we're doing now is translating together beginner level stories. It is kinda working, he is learning new words...but he tends to put a loooot of time and energy into thinking, so after 10 sentences it's been an hour and he's exhausted...and he doesn't seem to get how to apply what he's learning in actual conversations

Any adhd friendly exercises we can do together that might not overwhelm him??