Help for a Colorblind Minecrafter

Hey guys, I'm looking for some help. I don't know much about colorblindness, but my boyfriend who is red and green deficient wants to play minecraft with me but can't because a lot of the colors are confusing I guess. From what I understand, its like he can't tell the grass from the trees because a lot is green. Is there a mod or something that would put symbols or shapes on the blocks so he could differenciate them?