Unfortunately what seems to be missed in all this is the responsibility of TikTok. Why do they allow such things to be on their site, this is not the first time.
And I'm going to get slated for this I'm sure but it needs to be said to prevent further terrible deaths. Parents need to take responsibility of what their kids are watching on electronic devices. It is possible to block these out, indeed a number of sites are blocked or partially on my network. Yes it may involve a cost to buy something to help you do it, but thats part of the TCO of a device connected to the Internet.
I do wonder if a lot of this is the Mother feeling guilt.