Tell your daughter to tear up EVERY bit on carpet in her house,and throw it away. If she can't afford waxed hardwood floors,she can paint the plywood and use throw rugs. Throw rugs small enough to wash in the machine. She might also want to open the bedroom window in the child's bedroom a small amount to let in fresh air. Seriously.
Thanks for the advice.
They actually live in a rented house as they had to sell their house to pay medical bills. They have very good insurance, but when the bills climb to 6 figures, the co-pay can eat you up. The mother is almost an invalid. The baby is doing much better than he did as an infant and the house is really quite good.
You sound as if you are speaking from experience,a nd I will pass it along, maybe she could move his bed into a room with no carpet. I will tell her - thank you so much.