It says earlier in the chapter he'd been raised to avoid tampering with the unseen because his family believed it would invite misfortune. It looks like not all of his visions come true, so he believed that if he tried to tell her what was going to happen, that would just make it come true.
Is there any way around it? It's unfortunate that she died.
No, because there’s no precedence. Basically his power was useless in helping and could only cause him distress. Which is also bad, because his emotions would cause fortune and misfortune dependent on the positive/negative feeling.
In the novel, he tried once advising Seungtae based on the future he sees. Seungtae ended up in worse condition than what he saw in his visions. When he was a kid, he also saw Mrs.Seo's pregnancy way before his mother is pregnant with Muryeong. He kept it to himself all the time fearing that Mrs Seo wouldn't be able to have a safe pregnancy. That's why when Seungjoo is born he's even more compelled to protect him (in addition to the vision he saw when the baby cling to his finger). Muheun's ability is like a curse to him. He is always hoping he wouldn't see any kind of vision because if he does, he could barely do anything about it. It's something he has little control on.
Something that's fated to happen is bound to happen one way or the other. I have always think Muheun's ability is not about changing future but preparing on what to come. So if Muheun changed itd course even a little, there will be a ripple effect. The only time Muheun actively interfered with his vision is when he saw in his vision that Seungjoo is in danger. And that too will have its own ripple effect.
But, if Seungjoo was in danger. Shouldn't he interfere and let it happen? But, that’s me spitballing.
If you're thinking from Muheun's POV he wouldn't be able to sit still anyway if he sees Seungjoo in danger. Most of his visions with Seungjoo almost always like a short vision prior, during or after Seungjoo is in that particular situation. When Seungjoo was at the lake with him, minutes before Seungjoo jumped he saw himself crying helplessly trying to save Seungjoo. Like I said his vision mostly is not about changing future but to prepare for what's to come. He saw Seungjoo in his vision twice after he passed his spiritual energy to him. Both times he managed to catch Seungjoo in the nick of time. Technically he didn't change anything there.
Okay, I see.
Baby Seungju is a cutie! But, why didn’t that guy with the black hair tell Seungju’s sister about the warning if he did she wouldn’t die? Does he care about her?