Question:
Does a child in a year of aveilut for a parent visit their grave before Yom Kippur?
Answer:
A child may go to the grave of a parent during the first year to daven before Yom kippur. The reason why people don't visit the grave of a deceased person during the first year is not because there is something inherently wrong with going to their grave, rather because it is not a proper time to ask the deceased to pray for us. This is being that it is still a time of din for them and they actually need our tefillos. Therefore the child can go to the grave, but he should not go there to ask the deceased to do anything for him, however he may go in order to daven for the deceased. He may also go when there is a need, and during Elul and before Yom Kippur is called a time of need.
Sources:
Melamed Lhiyil Y:D 144, Nitei Gavriel (Aveilus) 81-5.