Therefore, the elder sister's behavior of signing the house sales contract beyond the agency authority has no effect on her twin brother, so the house sales contract has no effect. The newly appointed guardian shall take back the house through legal means and safeguard the legitimate rights and interests of the twin brother, and the consequences caused by the sale shall be borne by the younger sister. Things have to start with a case tried by the Gongshu District Court in Hangzhou. Li Bing, the guardian of two mentally retarded people, was sued, claiming that during his tenure as the guardian of Li Jia and Li Yi, he sold six properties of the two brothers privately, leaving them homeless.
After hearing one of the cases, Gongshu Court held that Li Bing, as the guardian of Li Jia and Li Yi at that time, should perform his guardianship duties according to the principle of being most beneficial to the ward, and should not dispose of the ward's property except safeguarding the ward's interests. However, he put it in the house of Li Jia and Li Yi for punishment, which seriously violated the interests of Li Jia and Li Yi. Therefore, the contract concluded by Li Bing is invalid for Li Jia and Li Yi.
After the guardian was changed, the new guardian, as the legal representatives of Li Jia and Li Yi, filed four disputes over house sales contracts with Gongshu Court, requesting to confirm that the four house sales contracts were invalid, and demanding the house users (buyers) and libing to return the houses and compensate the losses. Faced with this situation, the two are also very angry. They think that Li Bing, as a younger sister, and also as the legal guardians of Li Jia and Li Yi, has done such things that are incompatible with the law, so they appeal to the court and request to revoke Li Bing's guardianship qualification.