Keep hearing how Tank was just a poor tortured beautiful soul who was manipulated and abused by a dangerous sociopath. While I'm in no way defending what the tiny Filipino did, I think it's a bit of a simplified and convenient version of things.
The thing you have to keep in mind is what was on offer to Tank. In gay bear circles, being in an established stable poly relationship generally gives you a level of fame, prestige and notoriety on the local bear scene. You get known very fast. On top of the basic level of fame that instantly comes from being in a visible poly group, Dylan is actually not halfway bad at brand building - and he did this extensively through various social media platforms, so the fame was pretty global in reach.
Tank got a lot out of this "abusive" relationship - fame and notoriety for one thing - but also access to a lifestyle that he could not afford by himself. Living in a poly group with guys with decent salaries gives the household significant economies of scale. So you have a higher disposable income for partying and - in the case of Dylan's group - access to steroids. And again, building up and getting huge feeds back into the 'fame' in bear circles. Not only was the group very visible in terms of a poly 'familly' - but they had the ideal bodies (even if a great deal of it was photoshop - Dylan routinely shops abs onto his pics for example, it's not all that subtle). While there's a lot of suggestion that Dylan manipulated Tank into getting big - I don't buy it. Tank would have wanted that for himself, and so Dylan/the group setup was just a means to an end.
We can see that a lot of the power dynamic between the two of them was monetary, in that when Tank 'left' Dylan and 'broke the agreement' - Dylan punished him with financial penalties. The melodrama that played out when Tank left - ehh, just angry ranting from a guy wanting sympathy from his friends who he'd already pulled away from to devote time to his "Master". Of course he went back. We're talking about the equivalent of Geri Halliwell leaving the Spice Girls and realising she's no-one without the band.
The silicone body mods are a slightly more complex situation - but realistically, again, Tank would have wanted it. If he's a bottom he doesn't need his dick to function for fucking (no chance to change your mind though) - and indeed this would feed into an erotic self-image of being a "big bull designed to be bred" - he would be getting off on that. Did Dylan push it further than Tank would have been willing to go? We'll never know. Certainly there would have been a huge amount of 'normalisation' of the extreme modification within the group and the "silicone community" they were a part of. It's likely he wouldn't have gone as far if he'd not been in the group - but pinning that all on Dylan is a simplistic rationale.
For sure he was probably a lovely guy, but we're not talking about Mother Theresa here - this is a man in his twenties who won big on the bear fame jackpot, and enjoyed that lifestyle. He should have been aware of the risks of liquid silicone in the body - and especially so after the death of Peter Dovak last year. The dangers of liquid silicone reaching the lungs are well known, and my guess is that he was willfully ignoring the persistent cough (if indeed there was one), terrified of what it could be - or maybe everyone was just idiotically ignorant.
I'm not trying to defend or exonerate Dylan in any way - I have seen enough and heard from people who've met him what a repugnant cunt he is - but I don't think Tank is the blameless soul he's being portrayed as either.