What would be a good substitute word for the term "feed him"? Suppose you have a new employee in your office who happens to be from your own village (or the place you grew up in). Your another colleague, who is also from the same place, wants to give this new guy a treat. So, I was asking my colleague, "Why do you want to feed him?". But I don't feel good about this. It should be, "why do you want to take him out for a lunch?" or something like that. What should be a good sentence for this kind of conversation.
"Feed him" is a phrase you might use for animals, small children, and unwanted guests, so you are right to want something more polite. Some better options:
Where should we take him to eat?
Where can we all go to lunch?
What kind of food do you think he likes?
Where do you think he'd like to go to eat?
Do you think he'd like [X] food?
As well as others. Please take note that something like:
What kind of food do you think he eats?
is also not at all polite.
You have different alternatives as follows, depending on the context:
Why do you want to take him out to lunch/dinner?
Why do you want to take him out for a meal?
Why do you want to give him lunch/dinner/a meal?