Saw that story yesterday. A really great idea. According to the story, the service satellite can move on to rescue another in about five years time.
I wonder how extensive the service is, actually. Component replacement is likely not occurring as the failed satellite would had to have been designed with that in mind. To the best of my knowledge, geosync birds like that one were not designed that way as there was no practical way back then to reach them once they were in orbit.
My guess would be the rescue bird is just clamping on to the failed satellite and performing station keeping duties. The original satellite is so old it probably exhausted its fuel supply some time back.
