Indian tourist visas typically allow up to 6 months per stay, so that's why your passport should have at least 6 months before expiration at the time of entering the country. They will definitely ask for proof of return travel, but I feel they might still deny him at their discretion.
There is expedited passport renewal that you can pay a little more to have it done within a month.
https://travel.state.gov/content/tra...ort/hurry.html