Have they really escaped from Alcatraz?

According to all-knowing Wikipedia (smile):

In the end, authorities pointed out that the chances of the prisoners
surviving the trip across the bay were slim. At the time, there was no
discovery of robberies or car thefts that could have been attributed
to them, and the men were habitual criminals yet were never arrested
again. The FBI officially closed the case on December 31, 1979,
concluding that "no credible evidence emerged to suggest the men were
still alive" (though there have been many subsequent reconstructions
and yearly triathlon events are held to commemorate the event). There
have been sightings of the three men over the years which provides
circumstantial evidence that they might have survived. If Morris did
survive the escape and is still alive today, he would be 86 years
old.

In this video on YouTube, his cousin Bud Morris says he helped finance the escape and he saw Frank after the escape.

According to this article, the case was reopened in 1993:

The official position of the marshals service is that the inmates
likely drowned in their attempt, however, their spokesman, Dave
Branham was quoted as saying, “we think there is a possibility they
are alive.”

The article also claims:

The following day, a search party found the remains of the raincoat
raft on Angel Island, two miles north of Alcatraz. Along with the raft
was discovered a small plastic bag containing the personal effects of
the Anglins.

To further add to the mystery, footsteps were seen heading away from
the raft on the beach.

And this totally reliable account from mafiatoday.com claims to have interviewed him:

Frank Morris the most famous convict ever to escape from Alcatraz
prison and who was presumed to have drowned by authorities has been
found to be living under the assumed name of Padraic Welsh in a remote
part of Connemara on the western coast of Ireland.

Frank now 83 years of age decided the time was right to break the
silence and put the record straight after 47 years living a tranquil
life in a remote part of the west of Ireland. Recounting the night of
June 11, 1962, Frank said the escape went ahead as planned and along
with fellow escapees brothers John and Clarence Anglin they placed the
dummies in their beds, escaped through the vents at the back of their
cells and into the utility corridor. They then proceeded onto the roof
and down to the bay. There they boarded the raft they had constructed
and disappeared into the night to rendezvous with a boat which they
had arranged to pick them up, they then destroyed the raft and
scattered personal belonging into the bay to throw the authoritys off
their trail.

Frank having relatives from the west of Ireland and an aunt living in
Connemara had already organised passage to the Emerald Isle prior to
escaping as for John and Clarence Anglin he never heard from them
since and often wonders what became of them.

I think you have to choose what you believe.