Biokinesis? To move life?
Sorry, I couldn't help but point out the problems with the word hahah
Lots of people in psi communities don't like that, when people make up "-kinesis" words. Just a tip in case you ever hang out on a psionics forum and such, just stick with psychokinesis or telekinesis. It's like "pyrokinesis"; you're not doing anything different from psychokinesis, you're moving a material thing. In most communities it would be considered fluff to do that. Just so you know
So, about that ability...
I can see three solutions here:
A) He's actually shapeshifting on a small scope.
B) He's working some telepathy, suggesting to people's senses that his eyes are actually of that color.
C) He's doing something with the light, maybe some sort of telekinesis to keep a certain frequency of light from rebounding off his iris to change the color. Either making his iris absorb that light or simply making it not reach his iris, I don't know and we can't really tell at this point.
Most will say case A is unlikely, since it would involve modifying his DNA. I, though, think it's rather likely since that could explain why he has to go through that intermediate state, which would be illogical for case B. It could, however, be explained with case C. It all depends on how he's bending the light, but it could be that he's making the light rebounding off his iris go at a higher frequency, but making it shift too slow for the changes to seem instantaneous. (violet is the highest frequency of visible light)
So it's most likely not a mental thing, but a physical one. (Although we can't rule out B completely; the subconscious doesn't always work in a way a conscious mind can understand.)
Do you think he's doing it consciously or not? If he is, does he know what exactly he's doing, or is he just "doing it"? That's the thing with this sort of stuff, it's often either done subconsciously or it's done through reflexes and you don't know exactly what you're doing, you're just doing it. (I mean, we still haven't explained what exactly it is we do when we work telekinesis, right?)
As for the sickness, it would be healing. Healing's often part of a psion's spectrum of abilities; I wouldn't be surprised if someone with such a talent had more than one (instinctive or not) ability.
Is it normal? What is normal, really... Eyes do change color naturally (mine, for example, vary between green and brown) depending on the environment and mood, but not so rapidly and not with intermediate states like his. This is definitely not what I'd call normal.
