Is BSNL offering free landline with broadband connection?

There isn't any scheme from BSNL that offers a free landline along with the broadband connection. However, it should be in the hands of the local customer service centre. I must say your friend is lucky enough to get such an offer.
But, please note that for opting for a BSNL broadband, you will need a landline connection. Unless, you get a landline connection – Broadband connection cannot be availed.

It must be UP specific plan being run because in Tier-1 cities there is no such free phone plan running. It seems the BSNL is running some sort of promotion where they allocated 1 month or 1 year of free connection. As per the official website the plans doesn't offer any free phone service. So this must be complimentary given because the customer was kept for waiting line for connection. This may get interrupted and in future he may get the bills on the basis of the calls made.

BSNL broadband is based on the DSL functionality and it requires the copper wire of the voice based phone line. So you'll be allocated the phone number for your broadband. No physical device will be given if you just purchased internet plan. Though you'll not be charged or allowed for the voice calls, the number is still allocated to you. So the phone number is not free to his account. In your friends case this must be complimentary service.