I'm no expert on this but I think there are exceptions to the general rule of gheeba which are;
1. If you are asked about a person's character in reference to marriage, you are allowed to tell the trutyh and disclose any faults as there is another person's happiness at stake,
2. You are allowed to complain about a cruel ruler without them present,
and 3. You are allowed to talk about a persons character/ 'faults' if your intention in disclosing them is that you believe the person you are talking to is able to help you or this person with such matters.
Therefore presumably you can talk about someone else, your children included, so long as you are seeking advice and your intention is to gain help rather that simply backbiting iyswim?