scholar, that's not what people mean when they mean 'Greek culture had a substantial impact on Northern India', and it's definitely not what Cuahtemoc meant. That whole 'Pythagoras' or 'Jesus in India' type stuff is generally kookery, at best hyper-speculative to the degree where the speculation is useless. What he's probably referring to is the large impact that Hellenistic style Greek art had on Northern India and the nearer regions of Central Asia. That by itself is pretty easy to evidence, there are major Buddhist sites across the former Kushan territories which bear the hallmarks of Greek religious imagery and Hellenistic era architecture, and the integration of originally Hellenistic elements into Northern India's art and architecture is likewise not hard to evidence.
No, there are no Greek Buddhist texts, though there are the inscriptions of Ashoka in Old Kandahar which have bilingual Greek/Aramaic versions and which translate some Buddhist concepts into Greek terminology, and Bactrian Buddhists were writing in the Bactrian language which was written using the Greek alphabet. However, that seems like a very oddly specific marker for 'disproportionate impact', are you aware how few primary sources are available for that period in Northern India and Central Asia's history? Considering that the general belief is that Greeks had 'disappeared' in the region by the 4th century AD at the latest, and how few they were, and how long it had been since they ruled anything, it would be deeply surprising to find almost any Greek language sources from India in that period whatsoever. We have barely any primary sources from the period when Greeks DID rule in Bactria and Northern India, we're mainly reliant on coins...
The one major Buddhist text that clearly involves Greeks is the Milinda Panha, and that is only preserved by Burmese and some Chinese Buddhists these days, it wouldn't have taken much for that to disappear in its entirety as well. The fact that it exists is still relevant to the discussion, however, since it presents a Greek King, either King Menander I or II, as being curious about Buddhism followed by becoming a major patron of it at a relatively early time. The fact that any Greek actually manages to become mentioned by name in a Pali Canon text is pretty disproportionate in its own right.
Would be nice if people actually did some research on Greek culture in Central Asia and North-Western India before commenting, rather than just relying on the most easily found internet resources or assuming their own lack of familiarity reflects a lack of evidence of any kind.