Consuming Blight states that it cannot be used while casting spells. What does that mean?
Asphyxious cannot interrupt the casting of a spell to use his feat. For instance, if he had two focus points left, he could not spend them to cast Hellfire, use his feat, and then spend the last point. Nor could he cast an offensive spell, use his feat, and then use the newly-gained focus to pay to boost an attack or damage roll.
