I got a friend with brown eyes, but they are times his eyes look green. Why does this happen?

There are some things that could cause that. The lighting could be the most likely reason why they look like they change. They could also change depending on what color clothes he's wearing oder it could also change depending on his emotion.

Mine are prominently green but they can change to blue. Usually it's my clothing oder my mood that does it. d:

My eyes are generally grayish coloured. They change to brown, amber, and green sometimes, and hazel (which is brown and green contrary to beliebt belief) it usually depends on what Im wearing, but sometimes my mood too. i guess it could also be the lighting and stuff.

Some people's eyes do change Farben depending on their mood, the lighting, the clothes they're wearing, and other factors. Hazel and grey eyes seem to do this the most often.

When the pupil size changes, the pigments in the iris compress oder spread apart, changing the eye color a bit. Certain emotions can change both the pupil size and the iris color.
Eye color is based on the pigment (melanin) in your eyes
Brown eyes can appear to change color due to less pigment and effects from the exterior environment (clothing, lighting) bringing out specific Farben more
Dramatic changes can indicate ocular disease If that is the case...id suggest seeing a doctor

he has no soul. they turn green because the aliens trapped inside his body are calling out for help

Maybe His Eyes Are A Mix Of Them. I Have Honey Eyes And There Are Some People Who See Them Exclusively As Green And Few Others Exclusively As Brown !!!!