When they were in the shelter and he didn't want to leave, she said he had to trust her, and also open the door for himself so he could see she was right. Basically saying that he is seeing things and if he ever wants to get over it, this is a first good step in realizing the things he sees/feels isn't real. Also, when he says the storm is still out there and he feels the door and says, "You can feel it. Come here and feel it" - his daughter pressed her hand against the door and felt nothing, and his wife the same - then she said he needed to open the door for his own good, in the hopes he realizes what he is feeling/hearing isn't really there. After that, he had trust in his wife. He will look to her for advice on if he is seeing something or if it is real. At the end of the movie, his daughter sees the storm first, not him. He then turns to his wife, and at first, I thought she was about to shake her head to confirm that he was again, indeed, seeing something that wasn't there. But, then she looked down and saw the orange/yellow rain water on her hand - she looked and also saw the storm, and was nodding to him stating, "What you are seeing is real" coupled with the look of horror on her face. This leads me to believe that what he was going through, while most definitely weird, was real at the end, and had confirmation that he wasn't as nuts as he originally thought he was.