Technically speaking, debt collectors can only deal with you and, if married, your spouse. If you have an attorney, then bill collectors and collection agencies must deal with your attorney if you so indicate.
However, if you are unable to mentally or physically handle the stress of dealing with debt collection agents and bill collectors then you can designate someone else to deal with debt collectors on your behalf.
Section 805(b) — Consumer’s consent to third party contact.
Your consent to third party contact does not have to be writing. For example, if third parties volunteer that you have authorized them to pay on your account, then the debt collector may normally presume your consent, and accept the payment and provide a receipt to the party that makes the payment. However, consent may not be inferred only from your inaction when the debt collector requests such consent.
It’s best to do this in writing! Send a short letter that simply says you have designated so and so to handle your affairs concerning the specific debt in question.
With that said, be careful here! Designating someone to handle your affairs means they can also obligate you by promising things on your behalf. Be sure you and whomever you designate clearly understand your goals, intentions, and boundries.