Does the place where one person sat and another then sat remain the property of the first person, based on a Hadith attributed to the Prophet, peace and blessings be upon him?

It is probable that the friend is referring to the Hadith in Sahih Muslim: "Whoever gets up from his place and then returns to it, he has more right to it." Imam Al-Nawawi explained this Hadith by stating that if someone sits in a place (like a mosque) for a purpose and then leaves with the intention of returning (e.g., for ablution or a minor need), their right to that place does not lapse. If they return, they have more right to it and can ask anyone sitting there to move. This is the correct opinion according to the Shafi'is, whereas the Malikis consider it recommended but not obligatory. There is no difference between sitting in a prayer spot or on a chair in a hall. Muslims should deal with each other kindly and be willing to concede in matters not related to acts of worship, and submit to the truth, especially when a sound Hadith is used as an argument.