Their support amounts to making speeches at international conferences and not much else. The RoC is now headed for a showdown with the PRC remnants who control the North China Plain, and the west wants to see a united China under a pro-western government. It's also ironic that during Mao's era, the KMT in Taipei promised to spend the next Mid Autumn Festival in Nanjing, when it could very well become reality under a DPP government - which the KMT previously repressed.
If the PRC survived, it would appeal to Chinese nationalism to unite the vast majority of its population. Even most non-Han groups will support this, as being Chinese is a cultural identity that transcends ethnicity and religion. The Japanese tried to turn the Hui population against the RoC government during WW2. It ended up with the Hui imams declaring Jihad against Japan.
The remaining ones in the west are too small to credibly challenge the PRC's might.