What is Du He's relationship?

When Du was doing well in Shanghai in his early years, he was called a clever "little Zhuge", but the eldest brother of Shiliupu Wharf refused to do it. He resolutely asked his friends to introduce him to the mansion of tycoon Huang as a handyman, so as to "follow" this big ship and make a comeback one day. Chiang Kai-shek "mixed" in Shanghai in his early years and lost money in stock trading. During this period, he met Du (some materials mentioned that they became sworn friends) and introduced him to Guangzhou to take refuge in Sun Yat-sen, only to succeed later. This is the first worship. Chiang Kai-shek later became president in the legal name, but he could not defeat the warlords militarily and unify the whole country. So he saved the country, became sworn brothers with Feng Xueliang, his lineal Feng Yuxiang and Li Zongren of Guangxi, and consolidated his position by loyalty. This is the second worship. Military disunity will unify the rivers and lakes. Chiang Kai-shek worshipped many times in his life. The true and false brothers can be distinguished, but the nominal network has consolidated his personal strength.