Casa da Infanta, in Algarve, apparently is still owned by the RF and can be rented.
Great location, just over the beach.
They own several homes, neither of them directly related to the RF.
The family owns a Quinta in Santar in the Viseu district, appropriately named Casa das Fidalgas.
The house is mainly inhabited by D.Duarte's brother, Infante D.Miguel, duke of Viseu. https://www.vip.pt/minha-vida-e-em-portugal
On the aftermath of the 1974 revolution, a friend of the family who left to exile in Brazil, offered his Sintra residence to the Duke of Braganša, at a bargain price and that's the family main residence.
An old interview with several photos. https://www.sabado.pt/vida/detalhe/especial-sabado-12-anos---entrevista-de-vida-a-d-duarte-pio
Big yellow house and the park behind https://www.google.pt/maps/place/Rua+do+Campo,+Sintrafirstname.lastname@example.org,-9.3806728,121a,35y,85.48h,45t/data=!3m1!1e3!4m5!3m4!1s0xd1edabb5ff83055:0x4de12a1758e745b6!8m2!3d38.7928484!4d-9.3797418
When PM Salazar decided the revocation of the Banning Law and allowed the PRF to return, he found out that the family had scarce means.
Not at all strange since, after the death of King D.Manuel II in 1932 the PM "nationalized" the estates of the RF in the Foundation Casa de Braganša and the family could not touch a dime, despite the protests of D.Duarte Nuno, father of the present Duke of Braganša.
Not wanting to compromise the portuguese state with the RF, Salazar convinced Queen D.AmÚlia to name D.Duarte Pio (her godson) as his heir and the Queen left him several buildings she privately owned in Lisbon, in uptown Chiado on the grounds of the former Braganša palace destroyed at the 1755 earthquake .
For practical reasons, the family organized an appartment in Chiado, again appropriately at Duques de Braganša street, easier for their activities and for the children to go to university. https://monarquiaportuguesa.blogs.sapo.pt/entrevista-de-d-duarte-de-braganca-ao-318201
Until recently the Duke of Braganša had a large summer villa in Ferragudo, Algarve, a house he inherited from his aunt Infanta D.Filipa.
There were rumours that the house had been sold, but a couple of years ago, the family entertained the King and Queen of Belgium and their children as well as ADk Joseph (Habsburg-Palatine) and family.
Some very ancient photos https://monarquia.webnode.pt/news/ss-aa-rr-em-ferias-no-algarve-no-inverno-de-2003-25-de-janeiro-de-2003/
Do they have an ancestral home or do they live in an ordinary type house/villa?