Tommy is a Vietnamese-American man with midnight-blue spiky hair and the early signs of bags under his eyes and wrinkles.
He wears a v-necked royal blue and gold sports jersey, with a logo of a team in the middle, pants, and shoes.
Tommy is abusive like the rest of the family however, he does recognize the family needs Diane's help especially with the funeral preparations for his deceased father.
He is still condescending towards her, though.
This, by default, makes him the "nicest" out of Diane's brothers, although that is not saying much.
Tommy is a middle-aged Vietnamese-American man and another one of Diane's brothers. He does not have any distinguishable characteristics unlike the rest of his brothers, making him considerably generic.
Like the rest of his family, he still abuses and teases Diane. However, he does recognize her intelligence and admits they need her help with the funeral, although he is still condescending afterward.
During their meeting, Diane receives a call from her brother, about their father's passing. She is unfazed, much to BoJack's surprise, and she asks BoJack to come with her to Boston to pay respects—before heading back to Los Angeles.
When Diane arrives at her family's home in Boston, her family is revealed to be crass, rude, and obsessed with sports. So much so, that they had not taken the time to arrange a funeral, or remove their father's corpse from the living room.
Diane resigns to taking responsibility for their father's funeral, while BoJack meets the family and readily makes friends with them, since he had previously wished for brothers; having grown up as an only child.
After Diane makes arrangements to throw her father a funeral, none of her family show up, and her father's corpse is absent. It turns out her family is lounging at a bar and had chummed their father's corpse with the intent to throw his remains in the face of their hated baseball rival team's star, Derek Jeter.
Calling Diane a big shot for getting upset at their low expectations, BoJack tactlessly defends Diane by bluntly describing her career and living situation, saying she is not a big shot. Diane then flies into a rage, driving off with the truck, holding her father's chummed remains.
BoJack finds Diane at the city dump, where he consoles her, by telling her the ways he appreciates her. He reassures her, that she does not need to find closure or appreciation from her family since they are horrible to her. She should concentrate on moving forward and focusing her life, on where she's living, and simply not go back to her family.
He is also seen in the background when Diane is talking to her mom, Ma Nguyen, in a flashback from 2007 in the episode The BoJack Horseman Show.
Tommy shows up in Diane's crude sketches in Good Damage when she is trying to recall her father being abusive towards her while she was growing up and him pitting her brothers against her.