I don't really think so.
AfO might be able to attack Yu mentally once he tries but i don't think AfO would be able to break yu easily as he's on the state where he lost Sanity leading him to his Sadistic Reaper personality
Plus Yu's possession lasts for 5 sec, then forcefully brings him back to his body meaning while AfO is dealing with Yu in his mind, the moment Yu entered it
He'll take all of Afo's abilities with him as he returns.
Yu ftw
Being somewhat insane is not the same as having resistance to being mentally attacked. Yuu ACTUALLY has no reason whatsoever to resist being actively mobbed within his mind, being slightly crazy isn’t going to help that unless he has a specific reason or feat that suggests he does.
For those 5 seconds, AFO isn’t trying to break him, he’s trying to literally eat him and make him one of his quirks. He can forcefully make Yuu stay because he will absorb him and all of his powers while he’s in this mental world. His ability lasts 5 seconds when it’s not being interrupted by a being forcing him to not go back.
“He’ll take all of AFO’s abilities when he returns” that is even worse for him.
1) He’s not taking anything with him since the Quirks are sentient and AFO can absorb his Quirks and control where they go and what they do within his mental world FAR better than what Yuu can do. At best Yuu will cause a slight tug on his Quirks that will get immediately overwritten by AFO’s willpower either kicking Yuu out or devouring Yuu and taking his power instead since he’ll be in AFO’s turf. AFO literally thrives within his mental world, it’s where he’s at his strongest and where Willpower is the only determining factor, Yuu won’t be taking anything back with him unless AFO allows it.
Please read what I just said again. AFO can TAKE QUIRKS while in his mental world. He can literally steal Yuu’s ability away from him when Yuu tries to invade him, and completely assimilate his consciousness. Nothing Yuu has can even somewhat resist that.
Also, does it take 5 seconds to take 1 ability or does he need multiple seconds to take multiple abilities. AFO has thousands of Quirks. And if he takes just the original ability, he will get “All For One” which is the worst possible ability for him to take.
2) let’s say he does take all of AFO’s Quirks. He has now lost the fight.
He now has the AFO parasite inside him, so AFO takes him and his 10k+ abilities over from the since Yuu has no resistance to this of any kind. Yuu just becomes a copy of AFO or dies from AFO devouring his consciousness and taking his body for himself.
Also, for every ability Yuu takes, he loses his memory no? Imagine that on top of his abilities now trying to kill him from the inside with AFO smiling the whole time.
Taking AFO is the worst case scenario, Yuu will die a horrible death if he does.
And i think it's in his character to start with Plunder first because his og goal in the anime was to Loot all the abilities around the world (which he succeeded and now has 10k+ abilities, unfortunately they aren't specified)
And according to op, yu got prior knowledge meaning he knows what he can do, additional with what he will think of with Yu's mind reading
Then he dies or loses his powers at the start since AFO’s mental resistance/mental world is designed to consume things within it. Yuu has no resistance to this and will get overpowered in seconds.
The idea that he can steal all of AFO’s Quirks is also laughable when AFO can steal them right back in the mental world as well as absorb Yuu. There is nothing Yuu has that can even somewhat delay AFO’s mental world. And even should he take the Quirk “All for One,” he just becomes a meat puppet since the Quirk will take over his body.
If Yuu knows what AFO can do, then he knows he can’t win. Mind Reading is irrelevant since AFO still kills him with a breath while Yuu doesn’t have a single move that can hurt him in return. The best he can do is permeation and run away while reading his mind to know how to dodge properly. And AFO will eventually think he has a Quirk that reads minds or something like Danger Sense that alerts him when he’s going to attack.
Also, how does his mind reading work? From what I just read on the wiki, “Mind Reading” let’s him transmit the thoughts of others to other people, not let him read minds.