I would shorted how often you spray but increase how long you spray to at least a minute. This may not be why he is not eating but it will help his greatly. Try to add some variety to his diet. My vieled loves hornworms, he cant resist them. Maybe try some of those, dubia roaches, black soldier fly and the occasional wax or butterworm along with the feeders you already feed. Another recommendation that may not effect the problem but will add to his enjoyment of life is to upgrade his cage. The recomended minimum cage size for a male veiled is 2 feet by 2 feet by 4 feet tall. You may want to consider upgrading his cage so he has more space.