My child was pre-verbal. It was a cartoon of a baby with an outlandishly large head with its mouth held open by ravens’ claws being force fed various inanimate objects like doll heads and machine engines. I shut it down within seconds of seeing it.

Answering your questions in that context is sort of ridiculous, but I’ll give it a shot:

1. At that age, my kid would watch whatever was on the screen, basically slack jawed. No bandwidth for anything else, really.

2. See above

3. There was no conversation.

And to answer your comments accusative sibling comment, my kid found it by tapping “next” repeatedly, or whatever was in the sidebar. Fwiw, I know “the phone isn’t the parent,” but the grandparents don’t have the same sensibilities around tech.

Holy shit.

A TED talk about these videos https://m.youtube.com/watch?v=v9EKV2nSU8w

The OP said the child was a toddler. Depending on the exact age I'd suspect there wasn't much of a subsequent conversation given the lack of communication skills.

Aside from that, whether the child is enjoying them or not isn't all that relevant. My kid would enjoy eating ice cream for breakfast, lunch and dinner every day but I know what's good for them better than they do.