My childhood friend's wife is having an affair outside.

Everyone around us knows about it, except for him.
His wife works in medical devices, earning about three to four million yuan a year,
The large flat in Green Garden was bought entirely with her money, paid in full, about three million yuan.
His son went to study in Australia last year, with tuition and living expenses totaling around fifty thousand dollars,
His wife paid for that too.
He has mentioned it to us several times, saying, "My wife is really capable, she’s often on business trips,
Sometimes she goes out for three or four days and then comes back,
When she returns, she doesn’t go out again, just stays at home."
When he said this, none of us responded.
Not because we didn’t want to, but because we really couldn’t.
How do you respond to that?
Once, we were all eating barbecue at a street stall downstairs,
He drank two bottles of beer and then brought up his wife again,
Saying she had gone on a business trip to Shenzhen to negotiate a contract and wouldn’t return until next Wednesday.
I held back for a long time and then said, "I think I saw your wife the day before yesterday at Wanda Plaza’s entrance,
She was sitting in a car with a man."
He said it was impossible, I must have been mistaken,
She even video-called me last night from a hotel in Shenzhen, I saw the background.
Another guy sitting nearby kicked me under the table with his foot, so I didn’t say anything more.
After that, none of us dared to bring it up again.
He still doesn’t know that his wife’s occasional business trips are actually just renting an apartment in a neighboring city,
The man is a vice president of her partner company, and the car she drives is an Audi Q5 she bought herself.
What’s the hardest to bear is that his son already knows about this.
One time, his son told his older sister back home,
She later called me crying for over half an hour, saying, "Xiao Chao, your brother is so miserable,
He’s a grown man and can’t earn much money, and his wife is someone else’s.
What kind of thing is this?"
I asked if he should be told, and his sister said, "Absolutely not,
He has a weak heart, had a bypass surgery a couple of years ago,
If anything happens, everything will be over."
Later, when I saw him, I avoided looking into his eyes,
He was still happily telling me, "My wife transferred twenty thousand yuan to me next month,
Said I could buy whatever I want."
I said, "That’s good, that’s good,"
Then I got in the car, sat there for a long time without starting it.
What do you all think?