When Toby talks about taking his antidepressants he says that he didn't know who knew that he took them besides Kate. At that point the whole Pearson clan would have known since when she got pregnant with Jack he had stopped taking them and he got very depressed causing the whole family to worry about him and how.Kate was going to handle it.
While the timing of the death of Jonny Gammage who put the big three at about 15 its possible Niles Fitch who played him as a teen did not want to do it. In real life Niles Fitch is the cousin of Rayshard Brooks who died under similar circumstances (shot by an Atlanta Cop) in 2020.