Can a son whose parents died while displeased with him repent, and will Allah forgive him if he offers sincere repentance?

The first part of the question has already been answered in Fatwa No. 89102, and it pertains to someone who disobeys their parents after reaching the age of accountability. As for the second part, the evil deeds committed by the brother before puberty are not held against him, because he was not accountable, and there are no consequences for what he did, as the Prophet, peace and blessings be upon him, said: "The pen has been lifted from three: from the sleeper until he awakens, from the child until he reaches puberty, and from the insane person until he regains his sanity."