'For' is often interchangeable with 'to' in English though, when you're talking about an audience. It implies you're performing a service or giving something that's appreciated, it's more positive and emotive. Saying 'to' often feels more neutral, like you're simply specifying a target for the action.
So 'the man reads for the boy' would definitely be a valid English translation, if för can carry that same sense (like the boy wants to hear a story, or is too young to read, so the man does it for the boy's benefit)
Yes, åt would be a closer translation of English for here. But it would stress the aspect of "doing something so that someone else doesn't have to" more than 'for' would in English, so there's some overlap. Which is why for should be an accepted translation (it's since been added), but to is a better translation.
The following might me a little off-topic and probably dealt with in lessons yet to come, however I've been wondering how Swedish expresses indirect object / dative, which I (as a German and Spanish speaker) am used to doing though different article/pronoun inflections. I did notice how Swedish only has mig, dig, henne etc. for object pronouns. Is it common to use that för construction you made use of above instead? Or do dative and accusative have to be recognized as for the context?