Wow. Sounds like a tough situation. I think that this kind of testing usually includes some sort of look at the home environment. Is your son involved in the testing at all? Maybe he can express some concerns to the specialist himself? Also, who do the children spend most of their time with during the day? Their mom? Their dad? Does your granddaughter have any problems?

My son and daughter-in-law will be attending the testing tomorrow.  Currently my
son watches both children during the day.  He is recovering from surgery, from a job related injufy.  I usually watch the children on weekdays, while their parents work.
Several months ago my son noticed how happy our grandson is at my home.  He told my husband and me that he is a different child when he is at our home.  That sent up a red flag.  Our granddaughter clings to her dad.  Our daughter-in-law said that our granddaughter is close to her dad.  She said that their son is close to her.  We do not see that.  We wish that was the case.  We just looked at our stored pics in our camera, and noticed something very disturbing.  Our grandson is either crying or pulling away from his mom on several pics.
Our daughter-in-law is quite upset with the relationship between my husband and
our grandson.  They both light up like search lights when they walk into the same room.  I actually feel sorry for her.  She was an only child, who never had any children to interact with while growing up.  She never babysat.  Babies were a very new thing to her.  She likes a quiet house.  Therefore the children are not allowed to have toys that make noise.  Both children are restricted to a 12x12 living room and a hallway and 2 bedrooms.  The 2 Aketas have the run of the large family room and the large
kitchen area. While a Playpen seperates the areas of living.  
My son cleans the house, washes the dishes, scrubs the floors, washes the cars, tends to all outside chores, for the last 7 years of their marriage.  
She reads, plays on the internet and soaks in the tub and plays with the children.
I know what your thinking!  Yes he is a whimp!  
He is an adult and needs to speak up like one.  Therefore we fear that he will only
say what his wife will allow him to say at the evaluation.
My friends say that one of us should attend the session tomorrow, since we are the
caregivers 5 days/ week.   What do you think about that????
We reised 5 children and wish that we were not so involved with the raising of our
grandchildren.  We want to have fun with them and not be the babysitter.  However
they can not afford daycare for 2 small children.  So we will be there for them.
Thanks for your info and concern
Chris

It does sound like your daughter-in-law has some trouble coping with some of the harder parts of being a mom. It also seems like she needs some help learning how to bond to her children. Spent time with them! Play with them! You mention that she is jealous that her children are more bonded to their father. Do you think that she would be open to suggestions for improving the relationship from a doctor?

Also, how did the meeting do yesterday? Did you end up going?

It must be hard to be worrying about your grandchildren, but it sounds like they really need your support right now since their mom is still figuing the whole "mothering" thing out. It will definitely make a difference in the future.