The old man at home is eighty-three years old. He was fine a week ago, but after a week his memory deteriorated and he could no longer remember things. Is it related to Feng Shui?

It may not have much to do with Feng Shui. As people age, memory declines, which is normal. However, you mentioned that it was fine a week ago, but the elderly man's short-term memory loss has been severe, which may be caused by physical illness. It is recommended to go to the hospital for a check-up first. If the elderly person is fine but has natural memory decline, it is recommended to do more memory training, such as learning mnemonics, and then use the learned mnemonics to recite pi, poetry, ancient prose, etc. Regarding memory techniques, you can follow the WeChat public account: Super Memory Training Method to learn.