Can an indirect object become a direct object?

Hi everyone New member here and first question. I hope that someone can explain this to me. 

'they offered him a drink'

Here 'him' is the indirect object and 'a drink' the direct object.

 But:

'they offered a drink to him'

Is 'drink' now the indirect object and 'him' the direct object? Is that correct? If not could someone explain to me why not?... 


Thanking you in advance