I agree with you, but he wouldn't be the first parent to be in denial at the first sign of a medical problem. I think he sees Amber and all of her diagnoses and thinks most of it is a bunch of baloney (it is) and doesn't want Leah turning into that (with the endless excuses and talk of bipolar, depression, multi-personality disorder or whatever it is called now... and whatever else gives her excuses to lay on her bed all day)*. So, he dismisses it. But I do believe that if it happens again, he will deal with it. I don't think he is a bad parent, but let's face it, he's not very intelligent, so it may take him a while to "get it."
*I know depression is real and she probably does suffer from it, but she doesn't do a thing to help herself, and she uses it to excuse doing things she doesn't want to do.