NRI INVESTMENT & TAXATION

ONE OF MY RELATIVE IS NRI & WANTS TO INVEST MONEY IN BANK FD IN INDIA. MY QUERIES ARE :
1) WHETHER SHE HAS TO APPLY FOR PAN IN INDIA?
2) IF BANK DEDUCTS TDS ON INTEREST INCOME THAN SHE HAS TO FILE RETURN IN INDIA, IF
A) INCOME IS ABOVE TAX SLAB OF 1,50,000 &
B) INCOME IS BELOW TAX SLAB OF 1,50,000
3) WHETHER ANY FORM LIKE 15G CAN BE FILLED
4) WHETHER BENEFIT OF DTAA IS AVAILABLE.

PLZ REPLY ASAP & ALSO ADD ANY FUTHER POINTS TO BE KEPT IN MIND IN ADDITION TO ABOVE.

THANKS.