Does washing and shrouding the deceased atone for forty major sins, and if not, what is its reward, and what are the expiations for major sins?

Regarding the virtue of washing the deceased, there are two narrations: The first is from Al-Tabarani, stating that whoever washes a deceased person and conceals their faults will have forty major sins forgiven, and its chain of narration is strong, but Al-Albani declared it weak. The second is from Al-Hakim, stating: "Whoever washes a deceased person and conceals their faults will be forgiven forty times," and Al-Dhahabi and Al-Albani authenticated it. As for the virtue of shrouding the deceased, it is mentioned in a narration by Al-Hakim that Allah will clothe the doer with the silk brocade (sundus) and heavy silk brocade (istabraq) of Paradise.