Given their friendship and NF expertise he was offered a board postion.
An old friend decided to manipulate a sitution to his advantage.
NF stepped down from the board. The old friend released this news 3 or 4 days after this happened, not as immediately as he should have.
NF retains his shares, as he has every freedom to do. His share ownership has no material effect on the company.
The only argument you could make maybe is that he might not put his all into AVZ. But I think you just need to look at what he has to gain from AVZs success vs AJNs.
I use the word old friend, as this was made bery clear by Nigel that they have not spoken in a long time and do not remain friends. Obviously.