Juanita would not be able to walk around after being in a coma for 5 months. The muscles in her legs and arms would be too weak from being unused for so long.
When Tom first shows Lynette "I love you" in sign language, the first gesture he makes means "mine," not "I," basically telling Lynette "mine love you."
People in long term comas don't wake up suddenly. They will start moving around, opening their eyes, etc for days or weeks before they become "awake" enough to speak.