Great question. Based on the information you are providing, it sounds like they have an upper cross syndrome. The traps, sternocleidomastoid and levator scapulae need to be stretched and a good integrated exercise to help strengthen the weak muscles is doing a floor cobra. I would recommend doing an overhead squat assessment to determine what muscles are weak and what other muscles are tight prior to working with a client. Starting an exercise program without identifying potential muscle imbalances may lead to the cumulative injury cycle.