No, it is not normal or appropriate for parents or anyone else to make fun of or belittle someone's mental illness. Mental health issues are serious and should be treated with empathy, understanding, and support.
Mental health challenges can be difficult to cope with, and individuals experiencing them often need understanding and encouragement from their loved ones. Making fun of someone's mental illness can worsen their condition, lead to feelings of shame and isolation, and hinder their willingness to seek help or treatment.
If you are facing this situation, it's essential to talk to someone you trust, such as another family member, friend, or a mental health professional, about what you're experiencing. Remember that seeking help and support is crucial for your well-being.