Yes, it's perfectly legal, but is incredibly stupid in this case because of the liability. If you work on security this way, you are going to get sued eventual

Yes, it's perfectly legal, but is incredibly stupid in this case because of the liability. If you work on security this way, you are going to get sued eventually. If you are a monotributista or responsable inscripto, you will lose everything. A SRL (like a LLC) is the logical way to handle this kind of work. What I meant by illegally is that it would be illegal if he was already incorporated as a SRL and exporting services (he needs to do the escrow to do that legally).