The remains of a deceased person, or their ashes, must be buried and treated with respect because our body was a temple of the Holy Spirit, especially for those who are baptized. They have the right to be treated with dignity, and therefore, the proper place for burial is a cemetery, if possible. If burying the remains causes great difficulties, you are not morally obligated to do so.
However, if it is possible without significant challenges, you should bury the ashes with respect and offer prayers for the soul of the deceased. Yes, this is the proper course of action.