She's almost 70, spend all day watching q-anon style of videos (but in Spanish) and every day she's anguished about something new, last week was asking us to start digging a nuclear shelter because Russia was dropped a nuclear bomb over Ukraine. Before that she was begging us to install reinforced doors because the indigenous population were about to invade the cities and kill everyone with poisonous arrows. I have access to her YouTube account and I'm trying to unsubscribe and report the videos, but the reccomended videos keep feeding her more crazy shit.
I curate my feed pretty often so I might be able to help.
The first, and easiest, thing to do is to tell Youtube you aren't interested in their recommendations. If you hover over the name of a video then three little dots will appear on the right side. Clicking them opens a menu that contains, among many, two options: Not Interested and Don't Recommend Channel. Don't Recommend Channel doesn't actually remove the channel from recommendations but it will discourage the algorithm from recommending it as often. Not Interested will also inform the algorithm that you're not interested, I think it discourages the entire topic but it's not clear to me.
You can also unsubscribe from channels that you don't want to see as often. Youtube will recommend you things that were watched by other people who are also subscribed to the same channels you're subscribed to. So if you subscribe to a channel that attracts viewers with unsavory video tastes then videos that are often watched by those viewers will get recommended to you. Unsubscribing will also reduce how often you get recommended videos by that content creator.
Finally, you should watch videos you want to watch. If you see something that you like then watch it! Give it a like and a comment and otherwise interact with the content. Youtube knows when you see a video and then go to the Channel's page and browse all their videos. They track that stuff. If you do things that Youtube likes then they will give you more videos like that because that's how Youtube monetizes you, the user.
To de-radicalize your mom's feed I would try to
Watch videos that you like on her feed. This introduces them to the algorithm.
Use Not Interested and Don't Recommend Channel to slowly phase out the old content.
Unsubscribe to some channels she doesn't watch a lot of so she won't notice.
OP listen to this comment. YouTubes goal is to feed you as much related content to keep you on the site as long as possible. Radical content or otherwise, any engagement to them is positive. You can spend some time curating the feed so that the algorithm works in your favor and the algorithm will adjust very quickly to new interests.
I can confirm that this works quite well. I use these tactics all the time on my parents' feed to keep them from watching too many "crap" news, pardon my french. There's a very notorious news channel in our country that insists on feeding bad (and only the bad) news - I often remove their channel from the suggested feed play videos of funny fails/wins, cute cats, daily dose of internet and other happy nonesense.