Jw's view Catholics as part of the harot of Revelation. They will most likely quietly rejoice about his death.
There will certainly be no special mention of it in the congregations unless it is mentioned in the Watchtower, which is doubtful. And no elder would ever dream of mentioning a specific individual in his prayers from the platform [unless he were perhaps a prominent witness]. They would never pray for a religious leader dead or alive. I rarely heard anyone pray for anyone at all specifically except at funerals, and they never pray for the dead person, sometimes in a generic way for the family still living.