Q 1: What is the ruling on a man
whose forehead and nose do not touch the ground in Sujud (prostration)?
Is his Salah considered valid?
If the case is as you mentioned; the forehead and nose do not touch the ground during prostration, then his Salah is null and void. This is because it has been authentically reported that the Prophet (peace be upon him) said,
I have been ordered to prostrate on seven bones: the forehead..., and then he pointed to his nose [as one of the seven bones ordered],
the imperative mood essentially conveys an obligatory command. However, if he has an excuse which prevents him from making them touch the ground, his Salah is valid.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.