Does Indian origin US green card holder has 90 days gap period requirement from last visit to india to revisit india

I'm not certain I understand the details of your question - but here goes... If your mom is a permanent resident, you may come and go from the U.S. as she pleases. However, she should not take any single trip outside the U.S. that reaches 1 year in duration or she risks abandonment of her status. If she wishes to preserve her eligiblity for citizenship, she should not have any single trip that reaches 180 days and she should spend half of her days in the U.S....

Mom better not remain in India more than a few months at a time and mom also better apply for a Reentry Permit before leaving for India next time.

I agree with my colleagues. Your mom should not spend more than 6 months outside of the US. If she has to spend an extended amount of time in India, she should apply for a reentry permit before leaving the US. It would be best for her to meet with an attorney.