Sending such a letter now would probably be a bad idea - the CPS may decide it's better to send the kids to a foster home instead of letting them stay with the mother in that shelter - but how can the world ever become a better place if one should just accept injustice without even telling about it?

I believe the right thing to do would be to try to mellow out, write a letter and explain how much stress the family has been through - but in a factual, neutral tone and without any finger pointing - and send it whenever the situation has stabilized (with "homelessness" not being a topic anymore).

Perhaps ... just perhaps, the next time such a case appears, the employee on the CPS will agree it's better for the child to stay in a camper than staying in the shelter. Perhaps ... just perhaps, the CPS will intervene and look a bit into the conditions in the shelter. Perhaps it's unlikely, but it's even more unlikely such things will happen without the letter!