That is quite a map on its own merits. It doesn't make Afghanistan 'South Asia' in their conception.
Out of curiosity, do you know anything about the publication, Modern Diplomacy? It has a lot of interesting coverage that isn't generally available elsewhere, but I have no idea how much and in what ways to trust it.
The concept of ‘Akhand Bharat’ dates back to the 1930s and the map is displayed prominently in the newly built Indian parliament last year. So, it is not some fringe ideology,
Rationally, it's still fringe. Like many far-right parties today, in Europe, the US, Latin America, etc., the BJP has built popular support for fringe ideas.
We too quickly forget our history if we don't expect that or think popularity confers rational or moral legitimacy: Mao, Lenin/Stalin, Hitler, not to mention Pol Pot, Suharto, Pinochet, etc etc. were very popular.
Out of curiosity, do you know anything about the publication, Modern Diplomacy? It has a lot of interesting coverage that isn't generally available elsewhere, but I have no idea how much and in what ways to trust it.