In
Robin J. Fowler v. Commissioner (155 TC No. 7), the petitioner's CPA firm had the client e-sign a paper-filed return and attached the signature certified ("second submission") to the return.
In this thread,
viewtopic.php?f=10&t=19301&p=167032, I questioned whether this constituted a proper filing.
It is an interesting concept. One that might help you out if permissible. One that might help us all out if we got some guidance. I would like to think the petitioner's CPA firm had a good reason to do that (like prior successes).
Normally, in your situation, I would prepare for paper filing on my end (all the "sign here stickers" etc), hand sign myself, then FedEx to the client for hand signature and mailing to the IRS. Probably to the spouse in India first, then the spouse in India will need to FedEx to the spouse in the US, who can mail USPS to the IRS.
Good luck. Those expedited FedEx fees to India won't be cheap. Although, you're on the west coast, so maybe not too bad.