The goalkeeping legend had high praise for the French goalkeeper.
The former goalkeeper believes the striker will only leave Everton for another Premier League club.
Everton goalkeeper Joel Robles became the club's first choice last season.
Hennessey has a year left on his Crystal Palace contract, while the Toffees are down to just one senior 'keeper.
David Moyes has been linked with a return to Everton.
Everton are on the lookout for a new manager following the departure of Roberto Martinez.
Everton are having a disappointing season in the Premier League.
Neville Southall believes a lack of direction is to blame for the Toffees' failings.
The former Toffees goalkeeper has criticised Bill Kenwright and co.
The Everton manager is coming under massive fire after the Merseyside derby last night.
The USA keeper cleaned out Andre Ayew by reacting sluggishly to a John Stones backpass.
Neville Southall does not believe that Simon Mignolet is a Liverpool standard goalkeeper.
Everton legend Neville Southall has backed manager Roberto Martinez to turn the club's fortunes around after a terrible start to the new season.