Does the knowledge of doctors that offices write research for students affect the ruling on this writing, and is working as a proofreader in these offices forbidden, given that the proofreader does no more than correct linguistic errors?

Doctors knowing that offices complete research for students does not permit this action, because it is cheating and forbidden falsehood. As for working as a linguistic proofreader in these offices, there is no harm in it in principle, but one must avoid proofreading research completed by the office for students, so as not to be an accomplice to sin and falsehood. As for research that students have completed themselves and need linguistic proofreading for, there is no harm in that.