The Courthouse News site mentions a lift was clearly visible at another gate yet nothing was done to get permission to use that lift or to borrow an aisle chair from another airline. It also mentions that when he left Nantucket, two days after his arrival, neither the lift nor an aisle chair were available, either.

Assuming that article correctly represents the above details, Delta acted very disrespectfully, illegally, and quite frankly, stupidly.