I’m doing green highlights on black dyed hair please help

So basically I thought my bf wanted green tips so as I was dying his hair black I left the ends natural. I had one more section to do when he clarified that the photo had green on the shaft and black on the roots and tips. So I need to bleach the shafts of his hair tomorrow (we dyed it today) is that going to melt his hair?? I went to cosmo school and I know it’d be really bad for the hair but if he’s not going to change it will this melt his hair cause otherwise I can’t fix it at all and he’s going to be so sad 😭😭😭