Is this childs well-being at risk?

An acquaintance is extremely busy, has 3 children. A kindergartner, a 3rd grader, and a 2 year old. All 3 children seem to be bathed irregularly. Their clothes generally smell sour (like left in the washer too long?). The older 2 can "fend for themselves" somewhat, but the toddler is pretty dependent. He is extremely small for his age, and his hair is thin and has a very receded hairline. He generally looks dirty, but his diapers never seem to have been left on too long. When I have him in my care, he has a hearty appetite, but doesn't seem overly hungry. Within the next couple of months, I know that the parents will have more time. But in the mean time, is this something that should be addressed?