1,287. The Distance Between Graves

199:3 We don't bury the dead next to one another unless the board separating them  can stand by itself and is at least six finger-widths thick. When possible, one should act stringently and there should be six handbreadths between one body and the next. However, a person may be buried together with their child or grandchild. The general principle is that any child who may sleep with the deceased in life may be buried with him in death. However, an adult son and his father or an adult daughter and her mother are not buried together.  Even children are only buried with a parent when they are buried at the same time; if one was already buried, it's prohibited to bury them together.

199:4 We discussed in chapter 163 that if a baby boy died, we circumcise him next to the grave and give him a name. Similarly, a baby girl is also given a name. The chevra kadisha (burial society) must be informed about this.