bonesiii wasn't banned, just suspended from posting for bad behavior. What happened was that he abandoned his account after he was suspended and never got back to the staff to clear up his problem. If bones wanted to come back, he would need to PM the staff first to work it out, then he would be allowed to post again. I learned this from a staff member friend on the website, back when I was lurking.
Anywho, I remember that the Ta-Metru Mask Makers threw out Kanohi regularly for being cracked or flawed in some way. Only perfect Kanohi were passed to Matoran and worn. Now this could have been due to the Matoran's impeccable fashion sense (lol Matau) but I tend to doubt it. I think cracked or flawed masks would fail to keep the bearer conscious. However, repairing the mask (as Vakama did with the Mask of Time) would likely fix the problem entirely.
I recall that the Masks were failsafes by the Great Beings in order to stop Matoran overwhelming other powers in the MU by sheer numbers. IIRC, that would mean that the masks are less of a source of power for the wearer and more of a "contact circuit" for power. Like a light switch: turn the switch on (put the mask on) power flows to the brain, and the wearer is conscious. Turn the switch off (take the mask off) and there is no power to the brain, and the bearer is unconscious. A light switch has no power of itself (witness power outages) but if you damage the switch, no power will flow through it. Does that make sense? Repair the switch, and power will flow through it again.
If you want a Matoran who is barely alive, aka comotose invalid, for your story, I would suggest having some other body system be damaged and imperfectly repaired. We know this happened in-story (see: Karzanhi's Matoran) so it's not out of the question for your fanfiction. Just make it seem realistic. You got this.