Immobility, loss of sight, and now... incapability of summoning energy. By all means, Pitoni is dead meat. Especially with that burning star of white descending upon him.
Apocalyph's white light granted immunity. However, as a side effect, the one who was enshrouded in it could not use their abilities, just like they would not be affected by any other ability. This was the reason why Enzo was worried when Yenn had advised him and Apocalyph to coat themselves with the sharp white coat. Because then, her psychic messages would not be able to reach them.
Now, you might be wondering, why hadn't Apocalyph just enshrouded Pitoni from the start? If the immortal was ridden of his ability to use multiple Abilities, then he would not be as much trouble as he was. But then, you'd also be forgetting that Apocalyph's white light practically made its wearer indestructible.