Diseased mugo pine
This has been going on for several years, and I have addressed it by removing dead branches. However, i think i should have been more aggressive. Another mugo close by is also affected, but not as severely. I suspect this plant is beyond saving. If so, please advise if there is something i can do for the mugo that is not as severely affected. Thanks very much.
This looks like a mugo pine, a common landscape shrub. It also commonly gets a fungal disease which slowly kills it. Browning starts toward the bottom and kills the shrub progressively over a number of years. Yes, the pictured shrub is beyond saving.
Once a branch is infected, it cannot be saved. On your healthier pine, if you can prune out the infected branches and still have a viable, attractive shrub, you may want to attempt to save it, or at least slow down the infection.
Some success has been reported preventing further infection by spraying with a fungicide containing copper starting about mid-April and spraying 3-4 times at 2-3 week intervals. However, simply replanting with a different species may be the best solution.