is it illegal for child peotective services to tell the parent theyre not going to get thwir child back

this may not be "controversial" but this is like the only group im active in. anyway, i have this mother in one of my classes. long story short shes made a few mistakes and lost custody of her child. shes going through the steps to gain custody, taking rehab classes, exsponging her record, going to autism parenting classes basically doing everything required by DCFS to reunify her with her son.

today in class she told us the dcfs case worker told her she cant twll her son shes gonna get him back, she cant buy him toys, and she needs to get the thought out of her head that shes gonna get him back.

to me that didnt aound right, i always thoigh the goal is reunification. And rehabilitation for the parent if needed. Her son is 4 yrs old and is autistic with sensory issues. Its said that at age 6 its harder for social services to adopt a child out, but shes really working hard to get her child back. So i thought id ask yall what u thibk based off this info.

Is it ok for dcfs to say this to her? Is this illegal? And would it be worth it for her to protest dcfs?