I'm not sure why "Il achète sa nourriture et boisson" isn't a correct translation here?
The "boisson" needs the "sa" before it
I thought he was buying his own food and drink. and why manger rather than nourriture?
The problem of course is the presence of the pronouns which do not give any differentiation between people. Duolingo wants the idea "This man is buying the other man something to eat and drink". Have you reported this ambiguity?
I think Duo takes both of them as correct answers. "Il achète sa nourriture et sa boisson" is one of the correct options.
Why the "Il s'achète" instead of "il achète"? Is he buying his own food, or is he buying someone else's food?
"He is buying .." translated with "il lui offre ..." is exactly the inverse of the sentence correct? I think duolingos answer is wrong or at least very far fetched...
can we just say "Il achète SES repas et boisson"?
I missed this too, so I looked it up. Here's what I found: "The posessive adjective must be repeated before each noun." So Duo is right and we're wrong.
"Schaum's Outline of French Grammar: Fifth Edition" (Crocker, M; 2009, p. 55)
could it be "he offers him food and beverage" correct?
Doesn't seem like anybody in this thread has the slightest idea on how to approach the construction of this sentence... least of all me!