Not the hip joint
Usually it does not hurt to sit with hip arthritis
It may hurt to get up. Depending where it hurts it could be trochanteric bursitis if it hurts on the side of the pelvis; ischial bursitis or piriformis syndrome if it hurts on the bottom, coccyxgodynia if he pain is coming from the tailbone - called the coccyx.
Sometimes for comfort you can cushion you gluteal region with a pillow.