this is because

1. Article 2 of China's Contract Law stipulates that the contract referred to in this Law is an agreement between natural persons, legal persons and other organizations with equal subjects to establish, change and terminate the relationship of civil rights and obligations. Other laws shall apply to the agreements on identity relations such as marriage, adoption and guardianship.

Custody contract belongs to the scope of contract law adjustment, not to the agreement of identity relationship.

2, China inheritance law stipulated in article 3:

Legacy is the personal legal property left by a citizen when he dies, including:

Citizens' income;

(2) Houses, savings and daily necessities of citizens;

(3) Citizens' trees, livestock and poultry;

(4) Cultural relics, books and materials of citizens;

(five) the means of production that the law allows citizens to own;

(six) the property rights in the copyright and patent rights of citizens;

(7) Other lawful properties of citizens.

The contract does not belong to the scope of inheritance.

Therefore, when the custodian dies, the custody contract cannot be inherited.