Grayson's poor grades and mounting debt have made him feel so guilty for letting his parents down that he has a strong desire to die and persistently thinks about ending it all. Such thoughts are known as

Sui cidal ideation or having ideas about commit ting sui cide.

Explanation:

Due to his poor grades, added with the large amount of debt that he had incurred, Grayson begins feeling guilty towards his parents. This made him feel like he had let his parents down and often thinks of bringing everything to an end, desiring to die. Such manifestation of thoughts is known as sui cidal ideation, when a person constantly thinks of dying and ending all problems by killing himself or herself.