A:
It is
an act of Sunnah to put in the dead through the foot of the grave, if easier, laying them on their right side making them face the Qiblah (Ka`bah-direction faced in Prayer). However, since the dead child has already been buried, you did not know how to position him in the grave and this is why you do not remember whether you laid him on his right side or not and did not untie the shroud, you are not sinful for behaving as such. Nevertheless, you have to ask knowledgeable people about whatever affair you do not know about. (Part No. 8; Page No. 433) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.