Is the young man entitled to inherit the house his father acquired through an usurious loan, knowing that the father did not pray?

The ruling on inheritance from a father who abandons prayer varies based on the reason for his abandonment:

If he abandons it out of denial (denying its obligation): He is considered a disbeliever by consensus of the jurists (for someone who is not ignorant of its obligation, like one who lives among Muslims). In this case, there is no inheritance between you and him according to the majority of scholars. If he abandons it out of laziness: He is considered a Muslim by the majority of scholars, and you have the right to inherit from him.

As for purchasing a house with an interest-based loan, the sin of the loan falls upon the deceased, and the house is permissible for the heirs because the loan is related to the deceased's liability, not to the house itself. Sheikh Ibn 'Uthaymeen mentioned that whoever inherits usurious money, it is permissible for him because he inherited it through a lawful means.