Events of Red Dead Redemption 2
Horseshoe Overlook chapter
Thomas Downes first appears upon the player's first visit to Valentine, to which he can be found near the stables opening a fundraiser for charity. During Arthur's brawl in the saloon, Thomas intervenes in the fight between Arthur and Tommy. Afterward, he is seen giving donations to the poor in Valentine, and he may ask Arthur to donate. He is heard coughing while talking about giving money to charity.
At some point, Thomas became financially unstable and received a loan from Leopold Strauss. However, Thomas was unable to repay the loan, resulting in Strauss sending Arthur to get his money back. Arthur arrives at his ranch, and when Thomas claims he has no money, Arthur threatens and physically assaults him. During the beating, Thomas coughs blood which comes into contact with Arthur's eye. Edith warns Arthur that Thomas has an illness, so Arthur leaves the property.
It is later mentioned that Thomas passed away, presumably due to his illness but it is implied by his son that the result of the trauma he received from Arthur's assault added more to his death.
Beaver Hollow chapter
As the story progresses, Arthur noticeably coughs throughout the events of them, which progressively worsens. After the Guarma chapter, Arthur's appearance also appears to have deteriorated.
It is only then that as Arthur makes his way to meet Sadie Adler to bust John Marston out of jail, his cough begins to render him immobile and loses consciousness as a result. After being helped to a clinic by a stranger, Arthur learns from the doctor that he has contracted tuberculosis which will no doubt lead to his inevitable death.
This leads to the turning point in Arthur's downfall that makes him decide the person he wants to be in his final moments of life. Arthur himself speculates that he contracted the disease from Thomas Downes, as per wrote in his journal: "All them bullets shot at me, all them horses threw me, all them fights and it was the beating of that pathetic little fella Downes that killed me, I reckon". He will later say something similar to Sister Calderón if the player has high honor and completes her mission strand.
- Red Dead Redemption 2
|“||You won the fight already, surely that's enough?||„|
|—Thomas Downes to Arthur Morgan|
- His grave marker incorrectly spells his name as "Thomas Downs".
- Unlike most of the other loan shark missions, "Money Lending & Other Sins III" is mandatory, making it impossible to prevent Arthur from contracting tuberculosis.