Yes, Prem's rosy view of Modi is certainly at odds with much of what I've read elsewhere. But he's talking his book so I personally don't worry about the discrepancies.
In general, I feel Prem's writing often makes him seem avuncular to the point of being naive, particularly over the past few years. (The exclamation points ending every second sentence don't help.) I don't believe this is fully reflective of the depth of his thinking. Buffet also has the whole "Uncle Warren" persona, but there's certainly a very shrewd businessman behind the aphorisms and platitudes. Maybe not a fair comparison but perhaps you see my point.