DS1 has lots of appointments coming up, and I wondered if you guys could share your knowledge/ experience, as I am wondering about his DX - I just want the professionals to be a little more detailed I think. Current DX is ASD, definitely not AS.
I really think DS1 is demonstrating imaginative play.
He picked up a kitchen roll tube and pretended to be a Dalek, he is using any stick shaped object as a gun.
Play with figures is all combative still, but surely the above demonstrates imaginative play?
Also, what age would you expect parallel play to end and playing together to start? He plays long involved games with his sister, but if you listen, she directs them entirely - tells him what his people are to say etc. And his figures have to be what they are, IYKWIM - The Doctor has to be Doctor. When he is in a group, he is usually dipping in and out of games, generally peripheral, but he's not avoiding social contact, he just doesn't initiate it. He struggles a lot with greetings and goodbyes.
Solitary play is either puzzles, the Wii, the trampoline or running into things full pelt. Sensory seeking for sure.
Background: tested non-verbal IQ of 130+, verbal IQ of 90, speech disordered and pretty hard to understand out of context, a very loving, funny small person. With an explosive temper. 
You would think that 4 months after DX I would just accept it, but it is just not sitting right with me. 