First of all, the Entry Card is given to every passenger on any aircraft coming to Brazil and MUST be filled out by each passenger. It is the passenger's responsibility to present that Entry Card along with his/her passport or equivalent travel document to the Federal Police officer at the Immigrations checkpoint when entering the airport terminal from the aircraft. I have never heard of any of them simply forgetting to stamp the passport. I'm not doubting you, but are you absolutely certain that your friend didn't just forget to report to Immigrations and slip past somehow? Certainly, somebody must have checked through his baggage on arrival when he came off the plane?
Regardless, being in the country without either an Entry Card and stamped passport is serious trouble and could cause your friend to be deported. You said 'recently', but just how recently are we talking about here? A few days, a week, a month?
I would suggest that if it has been only a few days or so and your friend has his/her airline ticket stub, boarding pass and Entry Card that he/she either report back to the Federal Police at the airport (GRU) or to the nearest Regional Superintendency of the Policia Federal - Departamento de Estrangeiros with those documents, explain what has happened and beg for mercy. With any luck they will simply stamp the passport for the appropriate date and that will be the end of the problem. The longer your friend has already been in the country in this situation the more serious the problem will become and the more difficult to resolve.
If your friend simply decides to wait until he/she decides it's time to return home, without an entry stamp and Entry Card, there is going to be a major problem. It's better to try and resolve it now, before the return flight even if the Federal Police don't accept the explanation and ask your friend to voluntarily leave the country (which I doubt will happen).
Also, here in Brazil when the police are called to any kind of a problem they make EVERYBODY produce their identity documents. Should your friend happen to be in the wrong place at the wrong time, something happens and he/she's ordered to produce documents this can't be refused. Once the police find out that they're dealing with a foreigner they are going to immediately contact the Federal Police, if the documents aren't in order they will simply take the person to the Federal Police whether they were involved in whatever the situation was, or not!
 Cheers, ![http://yoursmiles.org/tsmile/flag/t67054.gif](http://yoursmiles.org/tsmile/flag/t67054.gif)
 William James Woodward, Brazil & Canada Expert - Expat-blog Team