People with autism spectrum disorder can dedicate many hours to activities that interest them. These activities may be more or less complex, but they are certainly relaxing and enjoyable.
The most important thing to remember is that the diagnosis doesn't change your relationship. It will likely help you find explanations for some situations that previously seemed inexplicable.
Every case is unique. That's why it's important to assess each child's abilities, skills, and challenges. But yes, a person with ASD can learn, each at their own level and with the support they need.