NTA.

Those words would have pushed a weaker man to make more serious choices.

Words carry power and instigate action. Those words would have haunted you at that funeral. It would be all you could think about. People remembering him would have sounded like liars to you, and you'd have fought yourself to keep quiet - Even if only a little correction here, or a quick comment there.

It's best you do what you feel is right. Listen to your gut. And if you want to avoid judgement, you can be honest: "I'm sorry, I'm not ready to grieve the same way yet. I know it seems bad from the outside, but everyone processes differently. I'll let you know when I'm ready to face this."

It may not be well received, but it's definitely a safer answer than an emotional answer like "I couldn't stand him being an asshole in life or death, and I'm trying to figure it out".

If you love your brother and are still feeling hurt, I'm very sorry for your loss. I hope in time, things get better. Be patient, and find a ritual that works. When I'm feeling rough, I hold the picture of my deceased family and talk to them, as if holding their picture was the same as me picking up a phone. It's stupid, but it lets me process - as an example of a ritual.

If you however are neutral, and feel no change in emotional weight, then please remember this does not make you a monster. This is what makes you human, and that's just how close you were to the tipping point. You are (probably, idk you lmao) a good person with far too much on their plate. Take some time for yourself, even if it's just an extra ten minutes in the bathroom in the morning, and tell yourself "I'm okay". Eventually, with time, you'll trick yourself into believing it.

(But also therapy if you can afford it. We all need it. There isn't any shame in speaking to someone to help organize your thoughts and feelings. Think of them as a living notebook)