In "Officer Down," Henry visits Frank for lunch and remarks that Frank would have more firepower if he swapped his revolver for an automatic. Frank's response? "I like wearing your gun, Pop." The look on Henry's face is priceless.
Added to when Frank adds that it was his grandfather's gun, which means that said weapon has been handed down for three generations in the Reagan family.
In S02E19, Jamie saves a baby from a burning building. There's a strong drive to award him for his heroism, but that means that his undercover assignment will be blown and his life will be in danger. Frank asks Renzulli to accept, and pretend that he was the hero. While Renzulli is pissed that Jamie didn't tell him, he accepts.
And then Frank gives Jamie a ribbon for his uniform's party salad in private.
First episode of season three "Family Business," Frank talks down Officer Blake, who's contemplating suicide over an accidental shooting he committed, in one of the most powerful moments of the show.
Also of note is why the officer is holding a gun to his own head; he reflexively shot and killed an unarmed and innocent man, and the guilt he felt over this nearly drove him to take his own life.
Season 3's "Framed": Danny has been arrested for drug possession, with it being obvious that a frame-up is going on. Henry approaches Erin's ex-husband Jack and asks him to be Danny's legal counsel. Jack accepts, and bills Danny for all of $1.
Season 4 episode "Drawing Dead," like "Family Business" , deals with the aftermath of an officer-involved shooting, in this case a 14 year old boy who was trying to escape from a shootout with the police he and his buddies were in. The officer saw him holding a weapon, but none was found at the scene (it was picked up in the chaos by a nearby storeowner). When we see Officer Montero later on, it's abundantly obvious he's been crying his eyes out and the possibility he killed an innocent boy is tearing him apart. It's such a clear demonstration of how much he cares about helping people as a cop that the audience will breathe a sigh of relief when he's finally exonerated.
In "Mistaken Identity", while investigating a hate crime against a mosque Danny remarks that he doesn't know why Muslims choose to live in the United States, but "the sign on the door says everyone's welcome so we gotta back that up, partner." Worth noting, Danny was in the Marines during the Iraq War.
When Henry suffers a heart attack while preparing Thanksgiving dinner, the rest of the family arranges to hold a complete turkey banquet in the hospital just so he won't miss it.
"In the Box" has Jamie and Eddie trying to raise funds for the funeral of an old man shot in the crossfire of a gang gunfight, after learning his wife of 50 years cannot afford a burial. They manage to get about $2,500 pitched in from fellow cops at their precinct. Once the widow shows gratitude, other customers at the diner she and her husband frequented begin pitching in money in droves.
In "Loose Lips", Jamie is out for his jog and notices the episode's victim all bruised up. He stops and tries to help her the best she can.
In "Love Stories," Gormley submits Danny and Baez's names to be considered for the Medal of Valor, for their actions in the drug raid in the season 5 premiere (the shootout in which Baez's brother was killed). Frank is reluctant to give a medal to Danny out of fear that it'll be seen by the public as nepotism. When he learns that Henry had passed him over for a Medal of Valor commendation for similar reasons back in 1986 (in an incident where Frank, while off-duty, single-handedly stopped a fleeing bank robber who had killed a teller and wounded three other people), he relents and ultimately decides to give Danny the medal. When they sit down for Sunday dinner, they decide to do a private commendation for Frank.
"The Road to Hell" shows Danny's more human side as he talks a woman out of contemplating suicide.
This line from Danny to women waiting in a plastic surgeon's office:
Danny: Alright everybody, I suggest you head home now. The doctor’s gonna be a while dealing with a murder charge. And, you all really do look good just the way you are, you know.