What is the reality of what my sister's father-in-law does by describing our house and other matters without visiting us, and claiming to communicate with saints, and what is the ruling on this person?

Divination (Kihana) is unanimously forbidden (haram), and a soothsayer (kahin) is one who claims knowledge of secrets and insight into the unseen. Going to a soothsayer is forbidden (haram), and believing him is an act of disbelief (kufr), based on the Prophet's (peace be upon him) saying: "Whoever goes to a soothsayer or diviner and believes what he says, has disbelieved in what was revealed to Muhammad (peace be upon him)." Divination encompasses every claim to knowledge of the unseen. A soothsayer commits an act of disbelief by claiming knowledge of the unseen because it contradicts Allah's (the Exalted) saying: "Knower of the unseen, and He does not disclose His [knowledge of the] unseen to anyone except whom He has approved of messengers." Claiming knowledge of the unseen through saints (awliya') does not fall outside this ruling, for even prophets do not know the unseen, and this is among the widespread polytheistic beliefs. What these men report is from the incitement of devils, and one must be wary of intermarrying with a family whose fiancé holds such polytheistic beliefs.