Allah (god) almigty can do whatever he wills, and as we know he says in the Quran in Surah Kahf, the Story of the "Fellows of Cave" in they sleep for many years but one may think how it is possible but the recent incident of "500 year old Girl" which says:
"Girl who was killed as an offering to the Inca gods sometime between 1450 and 1480, at approximately 11–15 years old.
mummy ever found, with internal organs intact, blood still present in
the heart and lungs, and skin and facial features mostly unscathed. No
special effort had been made to preserve her and 500 years later still
looked like sleeping children
YouTube : 500 year old girl "(Ref:01)
This can be a Sign by God which lead us to believe the Story of Fellows of Cave, Allah knows best.