My son and his fathers second toes slightly curve toward third like in mybprofike pic is my sons foot. is this hereditary?

Yes it is: This is seen in my practice frequently. The growth plate in the toe due to hereditary reasons, grows unevenly creating a curvature of the long bone (phalanx). Hopefully there will be no symptoms. A possible friction may develop to the adjacent toe. Moleskin, lambswool and or foot powder may help. Hopefully bone resection or hammertoe procedures will never be needed.