I have not seen the show in question so my comments are on past PBS folk legend / fundraising specials.
There was one on Woody done quite some time ago that I have on tape and often watch. It has Arlo discussing his father with some of Woody's friends such as Pete , Rambling Jack Elliot , Sonny Terry etc.
They would then jam with Arlo on some of Woody's songs. There were also later singers whom Woody influenced such as Joan Baez , Judy Collins, and Emmylou.
There was an excellent one on The Weavers , and another on Leadbelly.
They were great shows and perhaps they will be repeated some day.
My only complaint is that they only air this stuff when they are fundraising.
                   Slainte,
                      Sandy