I can provide some insights on the topic.
The idea that if someone can sleep while you're upset means they don't care about you is not necessarily accurate. People have different ways of coping with emotions and stress. Some individuals may find it easier to compartmentalize their feelings and focus on the present moment, which could include sleeping. It doesn't necessarily mean they don't care about you; they might have a different emotional processing style.
Additionally, there could be various reasons why someone is able to sleep while you're upset. It could be that they are genuinely unaware of your emotional state, they don't know how to help, or they believe that giving you space is the best approach at that moment.
Communication is essential in understanding someone's feelings and intentions. If you feel upset or hurt by their behavior, it's essential to have an open and honest conversation with them about your emotions and needs. This way, you can both better understand each other and work towards a more supportive and caring relationship. Jumping to conclusions based on one observation without communication may lead to misunderstandings.