Getting a replacement passport in Portugal please help!!

Hi. My partner is Portuguese nationality and living in uk. and his passports are missing. He managed to get a new ID card at the consulate embassy in London which took forever. And we really don't fancy going through that again to get his passport issued. But I've read online that we can travel to Portugal and go to a passport shop to get this issued. We have a photocopy of his previous passport that is missing and it's actually expired now anyway. So it is a case of needing a new one anyway. Does anyone know how we go about getting a new passport at the passport shop in the airport ? Do we need to make an appointment or anything? I would really appreciate some help as I'm losing the plot with this passport story now as my other half just hasn't sorted anything yet simply cos he is unsure how. tHanks in advance , Lia