Our preschool uses the Tools of the Mind curriculum in an integrated preschool setting. While the idea is very nice and encourages self-regulation, speech, taking turns and is designed for typical and atypical kids - my 4 year old was completely "not interested". Most ASD children do not experience pretend play very well. What was your experience?
So, not all autistic children engage in "pretend play", but some do. In preschool, they are determining where your child needs to be placed at in kindergarten and first grade etc. All children learn different. Some are visual learners, some learn through sound, some by roleplay etc...
My personal experience, my son is a visual learner. He will learn anything visually. Talk to him about it, forget it, nothing. Talk to him with pictures now he gets it. My son pretend plays all the time, ALL THE FREAKIN TIME, he is 6.. acts like Lightning McCqueen (sp) from cars... rides on dragons from how to train a dragon, plays with play mobils, by walking the peolpe into cars and driving them around... what does this do.. promotes speech, so in preschool they were able to see that in a pretend play he may use his voice of follow directions better based on the play. Keep in mind my son is nonverbal emerging speech. But if it does not help, and you would need to ask the teacher, (kids do things different at school then at home) then a different approach is needed, like structure, task boards, etc. Right now they use role play with my sons speech, and its ok, he talks more at home, he just likes us more then them, not sure what to do about that...
I think I may just type up a general disclaimer to put on my profile but since it's not there yet, here it is. My opinions are based on my experiences. If it helps then great. If it doesn't then toss it aside.
I do not have any experience with Tools of the Mind curriculum. One of my sons never did any pretend play no matter what program I tried. His social skills fell short but it wasn't for a lack of trying. His social skills fell short mostly due to problems with regulating his emotions which resulted in an entirely different set of problems especially in the area of anger. Enough said on that.
Another of my sons loved to pretend but he did not interact with other kids. I thought at the time that he lacked the skills and he may have, but then again maybe he had the skills but just wasn't interested. I honestly don't know. What I do know is that now he has a couple of close friends and he does fine. He is still not all that social and since he is ok with that then case closed on that one.
At this point I feel fairly certain that the saying I heard a long time ago holds true. "If you have met one child with autism, you have met one child with autism." And boy does that make things difficult!
I am not sure what deficiencies you are wanting to address with your son but if you feel like the program may help then I would say give it a try. As long as you don't see any negative results it is difficult to tell what he may be getting out of it. Even if it appears as if he's not getting anything he maybe filing some of it away for later use.
On the other hand, if you see a negative reaction to it on his part, I would be wary of continuing with it.
I know that is not much of an answer to your question but that's all I have. Good luck.