The key is neutral point of view. Friend's and family come with bias. The bias's can be compounded by mentally ill friend's and family.
Therapist must meet with other therapists about their patient interactions. The second therapist acts a neutral third party to the keep the first therapist from losing their neutrality.
That is the ideal and the real world may differ.
I'm struggling with someone that looks to be having some real mental issues. The person believes I'm the issue and I need to maintain a therapist to make sure I'm treating this person fairly.
I need a neutral third party that I gossip with that is bound to keep it to themselves.