I don't know anything specifically about cognitive worksheets. I may not be understanding what you are looking, for, but this does not sound like the right route. She needs to be engaged with people more than worksheets. Yes, people who are autistic tend to be visual, so maybe I do not know what you mean by worksheet. But just having her go through math/spelling worksheets, even with you ,is not going to be pivotal. There are tons of worksheets for different skills, but I would need to know about what cognitive skills you want to work on.