To tell the truth, Zhang Menglong really didn't care about those two trillion US dollars; his statement that he was not interested in money wasn't just a humblebrag like that of Boss Ma.
Though Domte had no descendants, he presumably had a wife. The family had devotedly served the Zhang Family for thousands of years, and Zhang Menglong wouldn't have objected at all if the money had been left to his wife.
And what if it was given to those brothers and sisters? With just a word from him, Zhang Menglong was not one to disregard relationships; after all, these assets were located in Yinhei and couldn't be moved by Zhang Menglong. Who operated them hardly mattered, did it?
But there's a whole different concept between what one willingly gives and others coveting something they shouldn't. Zhang Menglong greatly admired loyal individuals and, naturally, he detested betrayers immensely.