He promoted his own welfare at the expense of others.
他不惜以他人利益为代价换取自己的利益。
2
An entity, such as a baboon, is said to be altruistic if it behaves in such a way as to increase another such entity's welfare at the expense of its own.
An entity, such as a baboon, is said to be altruistic if it behaves in such a way as to increase another such entity "s welfare at the expense of its own."