So literal that context is lost, that's our kids sometimes. They're good memories, those times as they get so humorous when they mean to be so very serious.
My son was only four or five when I played with him in his room. I tickled him and he is still ultra ticklish everywhere to this day. I growled and said "I'll eat you up!"
His expression became just as serious as could be, "You can't do that! There's blood in me!"
What a smart little man, maybe too smart for his own good? Still I couldn't help but laugh and that didn't go over particularly well either. I had to explain to him that we would never actually eat him and we treasured him far too much to let any harm befall him. That made him feel better, but he still didn't see the humor in what he said.
Now I try to teach him the meaning of a good joke once in a while. I try to teach him how other kids will make fun when they really don't mean any harm. One of the pitfalls of autism is that such a loss of context can last all our lives and we can be years behind "growing out of it" without support. It helps him to understand that a child who makes an odd comment is only trying to be funny and not hurtful. Helps him to understand that the best response is simply to laugh.
It's not such a natural skill to us. Even so, I hope I never forget that funny day with my son. It serves as one of the shining moments in watching my children grow. I value it as highly as seeing him take his first steps, or an achievement at school. Keep the funny and happy times in the back of your mind, they make the tough trying times a little easier to bear.