Sam Altman should make it a condition of his return that the current board be dissolved and have a completely new board picked to avoid such dramatics in the future.
The board members should have a high degree of trust and cohesion. That does not mean they should see eye-to-eye on everything. But lack of trust and backstabbings like this can create a poisonous atmosphere on the board and ultimately affect the company's ability to execute effectively. If the CEO has to worry all the time if the board is going for his ouster, this will resemble the HP and Yahoo boards of the 2000s decade.