Is a successor trustee/beneficiary required pay debt he owes to an irrevocable family trust?

Hi, About 10 years ago, my father placed all of his assets into a California revocable family trust (pour-over). As a part of this he appointed my sister as successor trustee and she signed the trust documents affirming this. She and I are the sole beneficiaries. A couple of years later she borrowed substantial sums of money from him - which she never repaid. In addition, he guaranteed a credit card for her, which she defaulted on, requiring him to pay. There is no mention of this in any trust or will documents. My question is as follows - Does she have an obligation to disclose this as a debt owed to the trust, and, if so, would it effect trust distributions? The trust is to be dissolved upon distribution of assets. Thanks, Brand