I have a cousin who is autistic. He's my favorite cousin too. Autism is a developmental disorder where people have a hard time communicating. 
How do you and your cousin communicate best?
Oh, it's very hard to talk to him. He doesn't understand people very well. I have to repeat myself all the time. In autism, people repeat their behaviors a lot.
That is understandable. Does he like to play games or have any other hobbies he specializes in?
He loves science so that's his hobby. Autism develops usually in kids early in life but some kids don't develop it until adolescence.
Are there any specific signs to look for in early development?
Early life speech patterns are symptoms to look for. You can intervene early on and help the kids gain their self care skills and other vital skills.