Giving undue favours to one's own kith and kin

One word substitute is Nepotism.

Nepotism: the practice among those with power or influence of favouring relatives or friends, especially by giving them jobs.
Favouritism: the practice of giving unfair preferential treatment to one person or group at the expense of another.
Worldliness: the quality of being experienced and sophisticated.
Corruption: dishonest or fraudulent conduct by those in power, typically involving bribery.