Parent GC Application - Apply from USA or from India

[mbabla]

Hi,

Thanks in advance for reading this post, and offering any advice/ comments.

As a US Citizen, I want to sponsor my 80+ year old Father.

I understand the process takes ~6 mos. if he applies after entering the US (he already has a multi-year Visitor Visa to enter), and then apply for Adjustment of Status if it takes longer than 6 mos.

My Question -

If he applies from India, how long will it take, and is the process any easier/ more difficult in applying from India vs. him being in the US?

Best,

mbabla