Perhaps Fr. du Chalard has also been quietly rewarded?
I'm not sure if that's a red cassock. In that picture, as well as the last photo from your original link (outside the church), his cassock sleeves appear to be black. It could be the alb has red inserts.
Red albs were used in Medieval times, but they were not necessarily restricted to bishops.
So this could be a practice or an indult that English-speaking countries are not familiar with, like blue vestments which are allowed in Spain on Marian feast days.