So this is how it is?

This story is told through the first person point of view. It is about a old man that dies of a heart attack but wakes up in an unknown body in world he knows nothing about. After taking damage from falling he realizes he has the body and powers he always wanted. The problem is that the original owner of the body as only a small sister to take care of and he doesn't know her name or anything. He doesn't have any memories from the previous owner of the body. He only has his memories from his live back on earth. There is no system to provide hints or to show stats, just and old man brain in a young man's body. Lost and confused how will he provide for his new found sister.