Foster Care worker here. Your concerns would likely warrant further investigation in my area. Not necessarily foster care, but further investigation for sure.
I say call.
As a previous poster stated, give every detail you can, about what you have seen, heard, smelled, how the child acts, appears (big difference between filthy clothes and not nice clothes) how the parent acts, smell of alcohol etc.
The person on the hotline will determine whether or not there is enough information and/or concern to even generate a CPS report/investigation.
If a report is accepted, CPS will investigate. They will likely interview the family at home, being that there is no immediate concern of serious physical abuse.
It will be their job to interview medical providers, teachers and family. They will involve the father, and determine if he was aware of the condition of the home, and the well being of the child, and whether he is an appropriate resource for the child if necessary.
Making the call does not mean foster care. Let the professionals determine where to go from the point of your call.