There is no scientific evidence to support the claim that the weight of a person's body increases after death. In fact, the weight of a body tends to decrease after death due to various factors such as evaporation of fluids, excretion, and the cessation of metabolic processes.
It's important to note that shortly after death, the body undergoes a process called algor mortis, which is the cooling of the body to match the ambient temperature. This cooling process can sometimes be mistaken for weight gain, as the contracting muscles release heat and the body temperature decreases.
However, any perceived weight gain is likely due to misunderstandings, misinformation, or inaccuracies in measurement. It's essential to rely on scientific knowledge and accurate information when discussing such matters.