Is he obligated to offer expiation if a man swears to complete a matter while in a state where he might not be in control of his emotions, and what is the expiation in this case?

If a person swears to do something and does not do it, then expiation for the oath becomes obligatory upon him, unless he was unconscious due to intense anger. He is permitted to abandon what he swore to do if he sees benefit in doing so, and he should expiate for his oath, acting upon the saying of the Prophet, peace and blessings be upon him: "If you take an oath, then you find something else better than it, then expiate for your oath and do what is better." There is no harm in offering the expiation early or delaying it.