My father in his late 50s is shifting his investment allocation towards small-cap stocks and mutual funds. I think he has gone insane 😭

My father in his late 50s is shifting his investment allocation towards small-cap stocks and mutual funds. I think he has gone insane 😭 I’ve tried explaining this to him several times, especially about the risks involved with small-caps and the fact that valuations are already quite high. Apparently, some YouTube influencers and a few of his friends have convinced him that “small caps easily give 15–17% returns”. Now he is shifting all his money in smallcaps I advised him to either stay away from small-caps or at least wait for a meaningful correction instead of chasing them after such a strong run. But every time I try to discuss it, he gets furious and says “Mera paisa hai, tu mujhe mat sikha.” At this point, I’ve basically given up trying to convince him. My bigger concern is that he’s in his late 50s. This isn't money that can sit untouched for 15–20 years and recover from a major drawdown. If he takes excessive risk and something goes badly wrong, I’m scared that whole Financial burden can Lie on me I don't know how to approach this without turning every conversation into an argument. What would you guys do in this situation?