IMHO the duties and responsibilities of being a director should not be taken lightly. If it's just to make up the numbers then I would avoid, relative or no relative. If the post is on the written understanding that something will be offered when qualified, then that may be a different story. Quid pro quo.
Your friend should understand that if they are just putting their name to the BOD which is effectively just the relative running a one person show, you friend will still be responsible and recorded as such as a director if anything goes wrong. In the UK you can have one director but not in Ireland as far as I am aware. I know that because of this lots of silent directors are present in companies registers which I think is a nonsense situation that needs reform.