The 64-year-old retired firefighter had dreams of winning big, but became convinced that his luck had run out after suffering from a heart attack, cancer and kidney failure.
"Another thing gone wrong, I can't catch a break," said Brennan.
Brennan learned that he needed a kidney transplant- but there were 6,000 thousand people ahead him on the list.
Little did he know that, through his visits to the casino, he would gain something far more valuable than a jackpot.
Rivers Casino valet parker Jaime Maldonado- who was taught to get to know his customers- noticed that Brennan often looked ill.
"I noticed him in the summer where his arm had kinds of bandages," said Maldonado, 62.
Maldonado's wife had undergone two kidney transplants- and he had a hunch Brennan was on dialysis.
After talking to Brennan, Maldonado learned that his loyal customer had been waiting for a transplant.
"I said I'm going to pray for you Tim then after a while I got to known him a little better. I'm going to do more, I'm going to give you a kidney," said Maldonado.
"This gentleman approaches me out of the clear blue," said Brennan.
Brennan said he realized he had truly hit the jackpot when he learned that he and Maldonado shared matching blood types and no complications.
The transplant took place at Northwestern Hospital on December 27th.
Maldonado is back to work and Brennan is back at Rivers Casino.
"He's an angel," Brennan said of Maldonado.
The two have established a friendship and learned they have more in common than just their blood type.
Both served in the military. While Brennan was a firefighter for 30 years, Maldonado drove a Salvation Army truck providing food to firefighters during fires.