Swearing on somebody's life? Tempting fate?

[reallifeboogie]

My nephew swore on my mum (his grans) life that he didn't pinch something. He swore over and over he didn't do it. Two days later my previously fit and healthy mum became unwell and has subsequently been diagnosed with heart failure.
My nephew broke down in tears a few days later and said yes he had pinched the item and now feels that because he swore on my mums life that's why she's now unwell. I've never sworn on somebody's life and never would do so don't know what to think. Deep down I know its pure coincidence but I can't help but be angry with him. If he had just owned up in the first place I wouldn't have been angry just disappointed. Nephew 14 by the way.

Have you ever sworn on somebody's life or tempted fate in any way and something happen?

Don’t be ridiculous.

I don't believe it's tempting fate but I would never swear on someone's life and I would never trust a person who does. (Except for children who will just say anything to get out of a tight spot.)
Hope your mum's OK.

The only people that say that are lying.
It's a pathetic and childish thing to say and should cause immediate red flags.
Of course someone saying it doesn't make another person drop down dead. That's ridiculous. Tell the kid to stop lying and that using that phrase is just stupid and unconvincing.

You're an adult, you know it is coincidence so stop being angry with him for that.

He needs appropriate reassurance that the illness is pure coincidence. And he learned to swear on someone's life from somewhere - probably family.

Deal with the stealing separately.

No because fate isn't a thing

But a good lesson for your nephew not to be a lying thief

See also people who say to be honest before they say something, the implication being they aren't always honest

It's is just sheer coincidence, although I have had a similar experience.
Person I know swore on her daughter's hospital test that she wasn't being unfaithful, she was.
Daughter diagnosed with cancer days later.
It's a coincidence, I know it is, at the time I thought it was the most dreadful thing to say, and I still think it was now years later.