Tomas, 23, has autism, along with other developmental issues that have had a significant impact on both of the brothers past, present and future.
For the most part, he lives an independent life, but has limited social skills, and his ability to communicate, interact and maintain relationships are challenges David and his parents, Jana and David Sr., have learned to adapt to.
It's also why the Rittichs value their family time more than anything in the world, making the long trek west to watch David (and Harvey) over the past few weeks a memorable one for all.
The constant in Tomas' life, however, is a love of family, the Flames and, of course, Harvey the Hound.
"To have Tomas here and get to see the smile on his face every day - it's the best," David said. "I love him very much.
"It's good for me to keep working, keep trying my best. Everything I do, I do for him. I want to make him proud. He doesn't get that opportunity, so I'm doing it for both of us."
The brothers, naturally, don't know anything different.
The younger Rittich was born with those challenges and because of the love and unwavering support David has selflessly offered over the years, the two are closer now than ever before.
If there was ever an issue at school, the park, or anything in between, David took it upon himself to be his protector.
His mentor, guardian, and above all, his best and most loyal friend for life.
"Especially when we were younger, he didn't like it when things change," David said. "I always did everything I could to make him feel comfortable.
"Seeing him upset or (in pain) was the worst feeling.
"I hated it."
Worse, he could see the pain in the eyes of his parents, who had sacrificed so much for their children - more, David decrees, than he could ever re-pay.
The weepy-eyed, 6 a.m. hockey practices ("They drove me to the rink and stayed the entire time," David says) aren't exclusive to Calgary, it seems.
David's hobbies and Tomas' regular care meant Jana and David Sr. were occupied most of the day, with little time for themselves.
"Family is the most important thing of all," David said. "I don't know when I realized (that Tomas had challenges), but he's had it from the moment he was born, and my parents worked so hard for him. For both of us.
"I don't know anything else.
"But that's how it was, and you have to live with it. It was hard on everyone, but it brought us closer together.
"He's my inspiration."
This is Tomas' second visit to Calgary after making a stop in Stockton two years ago to watch his older brother break out with the AHL Heat.
But when he's back home - eight hours ahead in Jihlava, Czech Republic - the two make time to connect at least once a day over the phone.
"He always chirps me, and he's pretty good at it," David laughs. "I don't even know where he learned that stuff.
"It's the best part of my day.
"The way he's grown up, the way he fights and (handles) the challenge, I'm very proud. He goes to the school and he can go to the store by himself now, and he's really become an independent guy.
"Someone I look up to more than anyone else in my life."