Queiroz has first hand experience of the pair, being the main instigator of their move to Old Trafford from Brazilian league side Fluminense, and the 55-year-old has been involved in the twins' development ever since.
However, now that Queiroz has departed United in pursuit of the Portugal national job, he has apparently asked the twins whether they would like to play for the Portuguese national team.
The pair are eligible to play for Portugal as they both hold dual Portuguese passports, but both are unsure of what decision they will take.
The pair have played for Brazil at both Under-15 and Under-17 level, and appear to have high hopes of progressing to the senior team.
Speaking to GloboEsporte.com, Rafael said, "I still dream of the national team. I am young and still have a lot to prove."
His brother Fabio added, "Queiroz has already worked with us. He likes both me and Rafael and calls us any time. He really wants us to play for Portugal, but I don't know.
"Every (Brazilian) guy wants to play in the yellow shirt and play in a World Cup. I'd rather wait a little bit."
Rafael has impressed everyone at Old Trafford with the ease he has settled into the first team, making a total of 15 appearances for the side, scoring once, a superb half volley during the 2-1 defeat to Arsenal at The Emirates Stadium.
His brother Fabio however has struggled to secure a place in the side, having his time at the club hampered by a shoulder injury.
--Nick Turner, Goal.com