Scott was determined to do whatever he needed to in order to get his little brother back and though his link to Jean was long severed he projected his thoughts to her for an instant before she readied for another assault.
His idea was that since Apocalypse hadn't fully manifested that maybe if Lorna positioned some reflective metal and Scott fired at it to effectively hit Alex from multiple angles it could help Jean get an easier opening to pull the ancient mutant out of Alex, the best idea he had and he asked her mentally