I think it could go a number of ways:
First, it could be that White's character is positioned to make us like Tee's character more, and to inspire a redemption arc from Tee (maybe Tee saved Non?) - this would align with the more BL aspects of the genre, kind of lovey dovey vibes. That would mean White really was just at the wrong place at the wrong time though, but it makes the audience have at least one good moral character to root for, as everyone else has shown both good and bad sides. I think this is most likely, but I am hoping there's more to White's character.
OR
At some point in the past in their early relationship, Tee has told White everything that's happened, and White and Tee are also trying to get some form of revenge or sort the situation out in the present. This is unlikely as when everything first goes down at the house, Tee is scared of White finding out the bad things he has done in the past. That's partly why I think the first scenario above is what's going to play out.
OR
White could be somehow related to Phee and Tan's revenge plot. A lot of people have noticed how similar Phee's old school uniform is to White's school uniform, and it's confirmed White went to a different high school. This implies these two characters are linked in the past in some way. In this scenario, it's still a possibility that Tee saved Non in the past, perhaps with White's encouragement or help, but it's also a possibility that Tee did not save Non (unlikely that White would still be so in love with Tee in the present though if this is the case). However, I predict this is less likely because White's character in the present has been very innocent, and also affected by the hallucinations from the spiked joint. If he had been in on it with Tan and Phee, he would have known not to smoke it and wouldn't have had the hallucination about his skin getting boils. So it's unlikely he's a part of Phee and Tan's revenge plot. That leaves...
OR
White could be on his own revenge plot, unaware that Phee and Tan are also scheming. This would be a likely outcome if he was somehow related to Keng, the teacher, rather than Non. However, this is the least likely to happen in the plot in my opinion, given the good moral positioning of White's character so far and the bad moral positioning of Keng's character.
Another crazy theory I read somewhere was that White is actually just Non in disguise, and he got plastic surgery or something and came back to get revenge. This is really really unlikely though.
It could be any of these theories, something else entirely, or a combination of parts of all of them! So excited to find out next week lol