"was the last living Jesuit to be involved in an exorcism that took place in 1949"
Poorly written.
(1) Does this mean the last exorcism done was in 1949?
(2) Or that he was the last Jesuit to do so?
(3) Does this mean there are no Jesuits who either want to or are capable of performing exorcisms?
Apparently he was the last Jesuit alive to have participated in a particular 1949 exorcism. You're right, it's a badly written statement. Par for the course in contemporary news reporting.
It means that several Jesuits who were involved in a particular exocrcism. This particular exorcism occurred in 1949. All of those Jesuits are now dead; Fr. Halloran was the last of them to die.
As to your other questions: Yes, there still are priests willing and able to perform exorcisms. IMO there are not enough, but that's another discussion. I do not know if any of them happen to be Jesuits. The Society of Jesus is not currently the bastion of orthodoxy it once was (and should be again).