The levanter increased in intensity, Here I am, between my flock and my treasure, the boy thought. He had to choose between something he had become accustomed to and something he wanted to have. There was also the merchant's daughter, but she wasn't as important as his flock, because she didn't depend on him. Maybe she didn't even remember him. He was sure that it made no difference to her on which day he appeared: for her, every day was the same, and when each day is the same as the next, it's because people fail to recognise the good things that happen in their lives every day that the sun rises.
‐ A Paragraph from The Alchemist.
I understand the meaning but I found two things which are not used as the way they are usually.
After the comma a new clause starts with 'it's because' but the previous 'when' part of the sentence seems like it is left in the middle and it is incomplete.
In 'it's because' clause two times a "that" clause was used. First time it was used for giving extra information about 'good things' but the second time I can't understand what it is used for. I can't remember any use of a "that" clause which applies here. Like placed after noun or adjective; used as a complement; or working as a subject or object.
So how are these correct?