Based on the context and the answer, generate a question. 

Context: Apparently he 's home from the rehabilitation center and grumping around the house with his usual vigor . Did you know that ? I did n't . I stopped on the way home to visit Grandma and he came out from the kitchen . That 's how I found out . Everyone seemed in good spirits .

Answer:

he recovered fast and well from since his time in the rehabilitation center



Why was he grumping around the house with his usual vigor ?