What are 3 adjectives that show the relationship between Atticus and his children, Scout and Jem?

1. Respectful

It is not unusual for children to respect their father, but it is unusual for a father to give as much respect to his children as Atticus does. Though Scout and Jem lament the fact that Atticus doesn't fish or hunt like other dads, they are fiercely proud of him regardless. Like many of the adjectives that describe the family's relationship, respect is a quality that Atticus both preaches and practices, by doing things like making polite conversation with Mrs. Dubose after she insults him and listening to the children's side of the story every time, before making any judgement. Though the former example hurts Scout and Jem's pride, they appreciate Atticus's respect towards them and can understand why he approaches even mean and petty people with that attitude. 

2. Egalitarian

Scout and Jem don't call Atticus "dad," but use his first name. That's odd enough for most people today, which makes it even stranger in 1960s Alabama, but it shows how Atticus sees Scout and Jem as his equals. When Scout doesn't want to go to school, Atticus not only listens to her arguments as to why, he also responds to her (as he always does) without talking down to her:

"'I'm afraid our activities would be received with considerable disapprobation by the more learned authorities.'

Jem and I were accustomed to our father's last-will-and-testament diction, and we were at all times free to interrupt Atticus for a translation when it was beyond our understanding.

'Huh, sir?'"

In this instance, Atticus is treating his children as intellectual equals, a common practice for him.  

3. Honest

Honesty is one of Atticus's most important traits and one that he works hard to pass down to his children. He shows that it is important to do the right thing even when it's hard when he insists that Sheriff Tate not cover up what Atticus thinks is Jem's murder of Bob Ewell, saying,

"Thank you from the bottom of my heart, but I don't want my boy starting out with something like this over his head. Best way to clear the air is to have it all out in the open. Let the county come and bring sandwiches. I don't want him growing up with a whisper about him, I don't want anybody saying, 'Jem Finch... his daddy paid a mint to get him out of that.' Sooner we get this over with the better."

Atticus expects honesty from his children, but is also very upfront and honest with them as well. Atticus's honesty and openness about the situations that come up in his defense of Tom Robinson help Scout and Jem through the ordeal.