Avocado leaf?

[helptoall]

Hi , ive found a broken shell sanil and took him home for recovering, He has an old avocado leaf in his tank that ive used to pick him up with and yesterday he ate from it. its an old leaf tha is already has a black brown color. Just wantd to make sure its ok for him.
He also had a watery poop esterday but im not sure if its due the leaf feeding.

[jolovessnailies]

I am not sure hunni if that is ok for them or not. hopefully, someone on here will be able to help.

hugs jo xx