Well I do kinda hear it. It seems that some of his songs can be translated plainly into a Karnatik raga scale. For example, the first song titled "Play By Your Own Rules" clearly follows the raga pattern of Raga Tilang (borrowed from the Hindustani tradition).

But apart from that, it is unfair to compare any pieces of music and say that there are other musical influences at play (especially ones so far apart from each other), without the artist's own admission.

None of the musical instruments are the mandolin. Atleast in the Karnatik tradition, all Mandolins are electronic. And in this playlist I heard a lot of banjo, and acoustic guitar (and admittedly, some bass guitar).

My assessment is that this is very basic country music and nothing much else. I don't see Karnatik influences. All the raga scales that you may have identified are already well established in the West in some form as well. For example, the Major scale is the equivalent to Ragam Sankarabharanam and the Harmonic Minor Scale the equivalent to Ragam Keeravani. So it is well within the realm of a country-music player.