Prayer: Property with Minor, Insane, or Absent Heirs
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 863
If some of the heirs of a dead person are minors (ṣaghīr), insane, or absent, then using the property without the consent of the guardian (walī) of those heirs is unlawful, and performing prayers there is not permitted. However, there is no problem in using it in a normal way to start preparations for the burial of the corpse.