Sorry if the question sounds dumb.
In this last year DS (5, DX of ASD) has come on leaps and bounds.
His speech and language has developed fast like never before. He still is below the lower average for his age and still has much trouble with making conversations but the main thing is he has progressed.
With the progress in communication, came better social interaction, he isn't as solitary and aloof as before, he now responds most of the time and actually does seem to enjoy and even seek the company of other children, albeit in a very small group and 1 on 1 is much better for him.
His social skills are still imature for his age and he still tends to mimicry others as means to interact quite a lot but he has improved there too.
I'll now get to the point, his imaginative play seems to be improving too.
Like tonight he was using his long wooden train bridge as a gun, it's still basic but hey i never thought before that he would do this.
I checked with him and asked what is this to which he replied a gun. i was gobsmacked!
but in a good way for once. 
He still isn't able to make complex imaginative games, elaborate role-play and still is behind with this in comparison to other children of his age.
His own solitary play still is repetitive althought he is definately playing with more things now.
Like for instance he like to make his toys talk to each other but it is the same few phrases or very similar stories and play situations that get repeated each time. He doesn't expand very well on a theme.
When DD (2.5 y old) plays with him, he tries to take over and she has to follow his rules or else. So there are still some work to be done there even if he has improved hugely.
I'm just confused as i thought that pretending that an object is something else is the one thing ASD children just can't do. Was i wrong in thinking that?
DS has shown that he can now do this with the gun example, but we've always felt that he somewhat presented in an atypical way at times, so maybe that's why he can do this... or do some children with ASD eventually get to a level where they manage to do this?
Anyone else noticed similar with your child with ASD?