Tristan Thompson, NBA free agent and former partner of Khloé Kardashian, has sought legal guardianship of his 17-year-old brother, Amari Thompson, following the passing of their mother, Andrea, earlier this year.

In court documents shared by PEOPLE, Tristan explained that his father, Trevor Thompson, has been absent from Amari's life since 2014, leaving Tristan as the closest family member capable of providing the necessary care for his younger brother.

Amari faces significant medical challenges, including epilepsy and other conditions that require round-the-clock support.

Tristan has taken on the role of Amari's primary caregiver, and he has filed for sole legal guardianship.

Living together in Hidden Hills, California, Tristan has asserted that appointing a guardian for Amari is essential to ensure his brother's best interests are met.

He also highlighted that Amari is expected to receive a modest inheritance from their late mother's estate, which he intends to manage responsibly on Amari's behalf.

Moreover, Tristan plans to facilitate Amari's application for U.S. citizenship, as Amari was born in Canada.

The passing of their mother, Andrea Thompson, in January due to a heart attack was a tragic event that brought Tristan and Amari closer together.

At one point, they briefly lived with Khloé Kardashian when Tristan's home experienced structural damage due to extreme weather conditions.

Khloé Kardashian and Tristan Thompson share two kids, daughter True Thompson and son Tatum.

Although Tristan and Khloé have been living under the same roof, Khloé has clarified that they have not reconciled romantically.