This is a question from my son who is in the 2nd grade of elementary school

This is a difficult question for everyone, and I'm sure there isn't a single solution.
But in other words, no matter what anyone says, it's not wrong.
I would like to express my opinion this time.

① Why do we live
Honestly, there's no reason. If there is one, it's probably an afterthought.
The question “why do we live” arises because we are looking for a reason to live. People who already have a reason don't ask this question.
Incidentally, it doesn't matter if the “reason to live” is small. It's good that the morning coffee is delicious. It would be nice if there was something that made you feel happy. Japanese people call this “purpose of life.”
Your child seems to have a deep interest in thinking. Instead of giving a single answer, if you read in various genres that deepen your thoughts, the world will expand, and you will find “purpose in life.”

② Are there any good things about becoming an adult
It's there. This is because they stand on their own feet.
And this is because when you become independent, you will be able to do good things on your own.
Your child's physical functions are developing, and of course they don't have the ability to make money.
Right now, I still have no choice but to just wait for the “good things” to come along.
As this grows, you will be able to acquire “good things” for yourself.
So there are always good things. If that “good thing” is a “good thing” not only for yourself but also for others, it becomes even more “pleasant.”

③ Is there anything good about being reborn
I want to say “there is no place” here. I don't want them to look forward to reincarnation and despise who they are now and stop expecting it. To put it softly, “I don't know” would be the answer.

In a good sense or in a bad sense, it seems like children have a high hurdle for “good things.” Just being able to talk to your mother and listen may be a “good thing” for others. I want people to feel “I've already experienced good things” by being exposed to various worlds, whether it's a book, a movie, or a trip.

Sorry for the long and complicated text. I'll leave the rest up to my mom. lol
Please expand and deepen their interests.
Anyway, he's a kid looking forward to the future.
I pray that they will grow, using their strength and thought as weapons to resolve their doubts.

① Why do humans live?
There's no reason.
I'll explore this in my future life and present it to myself.

② Are there any good things about becoming an adult? If so, what good things are there?
That's something I'm looking forward to from now on.
If I plant good seeds while I'm a child, good flowers will bloom and bear fruit by the time I become an adult, and if I plant bad seeds, there will be some results waiting for me.

③ There are no good things in my life, so is there anything good about being reborn?
This is also the same as the question in ②, and it probably depends on how I live from now on.

Anyway, it's important to start from now on. Daily effort is also important. It's not when you die and be reborn; it's useless if you don't say “oh, that was great” in this life right now. So, while you're saying “there are no good things in my life,” you can't plant good seeds, right?

＜Additional Notes＞
The “Buddha and Sittakabutta” series is the best.
When I came across this after studying esoteric scriptures, I couldn't help but think, “Please bring this up from the beginning!” I think it's quite revolutionary that difficult Buddhist content, full of kanji, is so succinctly expressed in a 4-frame manga.
http://www.mediafactory.co.jp/butta/series/index.html
But when this is read, the source of my story will be revealed, so I wonder if that's a bit bad for me ~ (laughs)

① I'm looking for fun things to do.
② Just because you're an adult doesn't mean there are any good things. Being a kind person to your parents, younger brother, friends, and the people around you can do good things for both adults and children.
③ If you die, you won't be reborn. Changing words, actions, and ways of thinking will be reborn. Changing into a kind person without getting angry or rambling is being reborn.
Take a look at being reborn now.
Be kind to people like 00-kun.
From now on, try not to get angry, say bad words, or hit on you over small things.
Then I'm sure there will be good things.
Also, you don't have to compare yourself to your friends too much. I think it would be fun if 00-kun became even better by repeatedly practicing what he is good at.
Also, I think studying is difficult, but I practice over and over again, starting from an easy place. Don't worry about test scores or anything.
From now on, I will live with the goal of living a cheerful, correct, and friendly life.

appending
I recommend this book for kids.
“Buddha Ga Sensei” by Makoto Miyashita, Nagaoka Shoten

① Why do humans live?
A) Because I don't want to die. it would be painful if I were to die.
For example, it's painful when you hold your breath, and it's painful when you're hungry.
Also, when I died in my previous life, I thought “I still want to be alive,” so I was reborn and lived.

② Are there any good things about becoming an adult? If so, what good things are there?
A) There are good things. The freedom to decide how to live on your own will increase, and you can also get money that you can use freely. There are also things that are prohibited for children, such as driving a car, for example.

③ There are no good things in my life, so is there anything good about being reborn?
Answer) The better you do, the easier it is for you to feel happy, so your happiness will increase in this life and the next.
Also, if you call it “Namu Amida Buddha,” it is written in the sutras that it will be reincarnated into the Pure Land of Paradise in the next life.
No matter what kind of villain the Buddha is, he will not abandon “Namu Amida Buddha” and people seeking salvation.
However, the Buddha rejoices when he sees people doing good things, and laments when he sees people doing bad things.
It's similar to how a parent loves their child no matter how bad they are, but when their children do good things, they are happy, and when they do bad things, they are sad.

Q ① Why do humans live?
A ① I think everyone has various reasons,
The mother
I'm afraid to die,
I don't want to die yet, so I live.

Q ② Are there any good things about being an adult?
If so, what good things are there?
A ② Mother
I'm happy to be your mother.
There's nothing so good about it.

Q ③ There are no good things in my life
Is there anything good about being reborn?
A ③ Because I've only been alive for 8 years
There will definitely be good things ahead.
Just like something good happened to my mom.