Answer:
1. The author implies that the inability to feel for another is a sickness and its remedy or cure is Art.
2. Changing the word antidote to gift would make art seem like an endowment or talent rather that can prove helpful to him.
Step-by-step explanation:
An antidote is a remedy for a disease. It is like a medicine that can be used to cure an ailment. When the author said that art is an antidote that can restore our inability to feel for another, it implies that the inability to feel for another is like a disease whose remedy can only be art.
Changing the word antidote to 'gift' makes us see art as a privilege bestowed on a person that can serve a useful purpose for him.