I understand fully why you are concerned.
It does not seem to me to be wise to use strong smelling chemical products in a home with a small child.
Nor, as far as I know, should any of us be using spray products if we value the environment.
Whether you can say anything to your DIL depends entirely on what kind of relationship you have with her.
I would ease into the matter, by asking her if you might check the ingredients in the products she was using the last time you were there, as some of them seem to have given you hay fever.
This way, you are not criticising her cleaning methods, but seeking enlightenment, so you don't go and buy something you cannot use.
That you wouldn't either buy or use it is beside the point. I am trying to suggest a way of opening a discussion without offending her.
You may be surprised and she replies, "Oh, do you think it might be harmful?" in which case you can say it worries you a little.
Coming right out and saying you feel it might harm the child, will do no good at all, only cause offence.
My step-daughter insists on using anti - lice shampoo on her son every day before sending him to kindergarten because she is so shocked that some children have head lice. Her son has never had as much as one louse, and I did say I found it unwise to use a product that is not needed, as doing so might cause allergies, or simply cause the product not to work when or if it was ever needed.
She has chosen not to heed my advice, which is what I expected anyway.