Continuing with additional references.
• Rav Shach ZT”L was approached by a father whose son was expelled from a yeshiva. The Rosh Hayeshiva felt that this bochur would ruin others. The father cried to Rav Shach, but he refused to intervene. If the yeshiva needs to put the bochur out, that’s what needs to be. After this father left, Rav Shach summoned his gabbai. He stated that what he told the father was truth, but that the matter did not stop there. That was for the yeshiva. But what will be with this bochur? He cannot be sent to the street where he will deteriorate further. Rav Shach asked to be connected to another Rosh Yeshiva, and finally established the contact to place the bochur. He did not relax until that placement was completed. Expulsion may be necessary, but the child cannot be abandoned. (Mesoras Hachinuch, p. 87)
• Rav Gamliel Rabinovich shlit”a (Tiv Hachinuch p. 306) writes about the OTD child. “Therefore, when we approach this bochur, we first ask them how they are, and continue to speak to them ina friendly way to establish a connection. Everyone that has an inherent love for HKB”H needs to experience pain over those people that do not serve Hashem, and we must therefore invest our energy to be mekarev them to Hashem. The way to accomplish this is to not look at them askance, and not to concentrate on their faults and their inappropriate behavior. But the contrary, we must look and emphasize their assets, the mitzvos and good deeds they have done until now, as they have certainly accumulated many millions of mitzvos, D’Oraysa and D’Rabbonon as well as minhagim. And even if now they are not acting properly, the Chachomim tell us (Chagiga 27a) that HKB”H loves even the sinners. When we increase our love for them, they will recioprocate their love for us, and we can thus restore them to a closeness to HKB”H. It is clear to any Bar Daas that these bochurim need much kiruv and love, as even their physical situation is not favorable to them. And even if they appear to be physically happy, that is a façade. Being mekarev a single neshomoh is a zechus for generations, hundreds and thousands of potential Yidden who will fulfill mitzvos. (This was translated and adapted somewhat. The interested reader is encouraged to study this in the original, and the ensuing pages of the sefer.)