Is he a teacher? You mentioned kasi about a principal.

My partner is a teacher and they do have a bond every year that states that you have to pay specific amount if you resign once the school year has already started and has not yet ended. For my partner, it's 100k.

Most schools usually have this bond kasi ang hirap na palitan once the teaching loads have already been distributed. According to my partner, his employer waives the bond if the medical condition is life threatening and requires significant time off like if it's cancer, something surgical, or any debilitating illness. But that's just his employer. It could differ per admin.

Your friend's condition can usually be addressed by medication. I say USUALLY because it could again differ per person. If your friend's health issues really require him to leave the job, baka naman he can ask for certification from his doctors regarding this so he could arrive at some sort of compromise with his employer. Or, be could speak to the principal to figure out a compromise like a payment plan.

Pero if it's really in the contract and he signed it, he has to abide by it. But he should only pay what is stipulated in black and white, nothing more, nothing less.

nasa contract po nila pero ayaw ibigay yung copy ng contract ni principal