What is the ruling of Islamic law regarding marriage to a girl whose father refuses photography or greeting elders by bowing down to a ninety-degree angle or sitting cross-legged for men and kneeling for women, and threatens with a curse if this is not done, knowing that the young man fears falling into what is forbidden?

Bowing in greeting to other than Allah is forbidden, for it contains an abasement to other than Allah and an imitation of non-Arabs. The prohibition intensifies if it reaches the extent of bowing in ruku' (bowing in prayer) or prostration, and it may even reach the level of disbelief if it is intended to glorify the creature as Allah is glorified. You must advise your father with wisdom and patience, and seek assistance from people of knowledge. There is no obedience to a creature in disobedience to the Creator. If you fear hardship for yourself and it is possible to manage him with the lightest forms of greeting mentioned, such as sitting cross-legged, then there is no harm in that. If that is not sufficient for him, then there is no blame upon you to marry without his permission.