Is there any Sharia basis for the popular saying in Chechnya that the bones of the deceased separate in the grave on the thirty-ninth day, and that charity alleviates their torment?

The states of the deceased in their grave are among the unseen matters, and there is no specific evidence for their torment on the day thirty-nine. Charity and supplication benefit the deceased, and the people of knowledge have agreed upon the arrival of their benefit to them, and this is not restricted to a specific day.