MANILA — A Philippine court on Friday sentenced Imelda R. Marcos, the country’s flamboyant former first lady, to a minimum of 42 years in prison for creating private foundations to hide her unexplained wealth.

But it is unlikely that Ms. Marcos, a 89-year-old widow, will see any jail time. The court, which handles graft and public corruption cases, said the ruling could be appealed, and legal experts have said Ms. Marcos could fight a prison sentence because of her advanced age.

The sentence comes as Mrs. Marcos and her family have seen a political resurgence in the Philippines, having gained favor under the presidency of Rodrigo Duterte.

The court found her guilty of seven counts of graft, with each count punishable by a minimum of six years in prison. The ruling also automatically disqualifies Mrs. Marcos, who is a congresswoman, from holding any public office.