Hm, strange. For some reason, even though I watched it in Japanese, I didn't see Tobio die? I just saw Jumpu sniffing Tobio's hat and straight to Tenma being angry and deciding to rebuild him.

Censorship sucks.
In the American version of 2003, they changed Daichi's background story, censored out all mention of him ever being human, and instead fed us this weird and nonsensical story about how he has always been a robot.
I am not a robot. I'm a cyborg.
X-)