Dialogue and mannerisms help?

ewf speaks wise words here. Just...

You can listen us. Just don't believe us too easily.

Use "Ignore" button when it is useful. It makes being here easier.

If you take yourself too seriously, you will take feedback too seriously. So... Take yourself with light touch. Like...

 

I think a few minor changes could evoke a bit more emotional investment. I'm going to suggest a few tweaks, but please take them with a grain of salt. I'm no professional.

“Why do you insist on calling dad, Charles? He was your father too.” Lillian said, holding her cup with both hands up to her face.

"Why do you insist on calling him Charles? He was your dad too." Lillian cradled her cup in her hands, taking careful sips as she looked at Basil expectantly.

“He may have been my father but he was certainly no dad. I swear that he was waiting for every chance he got to throw me out.” Basil snipped back.

"Father perhaps, but not dad. A dad wouldn't jump at every opportunity to throw me out." Basil frowned and clenched his fists.

“He loved you, you were his son. At least respect the dead a little.”

Slight change - "He loved you. You were his son. At least respect the dead a little."

“The old schmuck deserved it, shoving me around like that.”

I don't like the use of schmuck here. It doesn't carry the weight I think it needs to. Perhaps: "Loved me? Interesting way of showing it." Basil spat. "He deserved it. He deserved worse for the way he treated me." - I'm taking the shoving out, because if she really did not see that side of their father, I think this would open up a different conversation. Is Basil willing to discuss this with her? Is this what he wants? Is he guarded or is he opening up here. Is her character the type who would ignore him saying that their father was physically abusive? These are the questions that come to my mind.

“Both of you were at fault and it’s no good to talk like that about him. Just because he wasn’t your best friend doesn’t mean he was a horrible father. Maybe you’re a schmuck for not letting it go.” She stood, roughly dropped her cup in the sink and propped her hands up on the counter. “I just wish you would see some light in the world. It would do you some good.” The young woman stomped off up to her room.

"You were both at fault. Just because he wasn't your best friend doesn't mean he was a horrible father." She tossed her cup into the sink, causing Basil to flinch. She took a deep breath and placed both hands upon the counter. "Maybe you need to take a look at yourself, speaking ill of the dead, of your own father?" She spun around to face him. "I just wish you would see some light in the world. It would do you some good." She threw her hands into the air and stomped off to her room.

“Well, it’s hard to see the light if it’s been burned out of you.” He said softly to himself, alone in the kitchen.

I have feelings about the light being burned out of him. It just feels off for some indiscernible reason, but I like him speaking softly to himself alone in the kitchen. It gives me a good visual with some feelings attached.

 

Now that I know you're only 14 @ThyRivalPoet, it explains a lot. You have a lot of living to do before you can write something this heavy. But keep writing it. By the time you're 21 and read it again it will be priceless.

 

In dialogue you don't just show us what the characters are saying, but how they are reacting to a particular event or conversation. For example, let's supposed your characters received the bead new of their father's death. Now, think about their personalities. Will they react Lightly? Sad? Angry? Or perhaps calm? Calculated? Maybe one of them killed him. Now that you established them to think about their reactions. Let's imagine they are in a coffee shop. The way their drink or grab the cup, can tell about their emotions. Grabbing a cup slightly? Smoothly? Squeezing? Hitting on the table? So yes, dialogue and mannerisms must coexist together.

But others on this post gave you already good pieces of advice. I hope this helps.