This page of our guide to Life is Strange True Colors contains a description of Part 4 of Episode 5. It covers the memories from the orphanage and the conversation with Alex's brother.
Your last memory is from the orphanage. Alex will be exhausted by now. She won't want to work with her brother, she doesn't want any more memories.
The brother is relentless, though. He's trying to get his sister to do it again, saying that this is the last memory she has to live through to understand everything.
Eventually, Alex will break and move towards a locker where she can sit. On your way there, you can look around, and you'll find a few mementos, documents and secrets.
Gabe will be there for her sister, he won't leave her side. It's a horrible memory that will make Alex break down more and more. She's going to get emotional.
Your task is to examine the thoughts of two couples. They're right behind the glass pane. Each of them has an issue with Alex, they do not want her, they claim that she is not a child for them. With every word, Alex will feel worse.
In the end, she won't be able to take it. The explosion of her emotions will make all the windows around crack. At that point, you'll have another conversation with your brother. He will tell you that you are not guilty of anything and that you have the strength to survive one more blow. You need to wake up and get out of the mine. It's time to show everyone the cruel truth.