There are two entirely separate things here:
- How much you are allowed to bring on the airplane (which is up to the airline), and
- How much you can bring into India (which is up to Customs).
The airline part is fairly straightforward: thanks to the magic of the Piece Concept, for all international flights starting or ending from the US, you are allowed to bring 2 pieces of checked-in luggage of up to 23 kg each per person, total 46 kg, plus 1 item of carry-on luggage of up 7 kg (usually) per person, plus a "personal item" (handbag, laptop, etc). So that's a grand total of 53 kg per person.
The airline does not care what you pack, as long as it is not hazardous. Also, unless you buy extra insurance, per the Montreal Convention they will only pay you an absolute maximum of 1131 SDR (around US$1600 at time of writing) if they lose or destroy your bags by accident.
Then there is the complicated part, which is Indian Customs. Customs & Central Excise publish a "Baggage Rules at a Glance" guide for travellers, which is 20 pages long (!), but here are some of the main points for a returning resident who has been away from India for more than three days:
- Unlimited amount of "used personal effects required for satisfying the necessities of life" (basically clothing, toiletries etc, but not eg. electronics)
- Up to Rs. 35,000 duty-free per person
- Additional limits for tobacco, alcohol, gold, silver
- One laptop in addition is allowed
- Up to US$5000 (or equivalent) in cash
All limits are per person and cannot be pooled (eg. two people can't bring back a Rs. 70,000 item for free). If you're a "professional" returning to India after at least three months working abroad, you get extra allowances for household goods and professional equipment; there's also an entirely different set of rules for visiting tourists.
All that said, Customs are a notoriously corrupt bunch and there are quite a few greedy sadists who appear to enjoy using real or imagined infractions of the rules to extract bribes or liberate people from their belongings. As ever, it's the poor manual labourers returning from years of toil in the Gulf who seem to get the brunt of this though, and they'll back off if you're confident and make it clear you know the rules (a copy of the official guide above won't hurt!).