The ticket purchaser is the customer and will always be notified of ticket developments. OP is simply the passenger named in the contract. Rather than calling DL, simply look at its privacy and data protection policy (online) and you will see that the customer will continue to be notified.

In addition, if the customer is an employer working through a corporate TA, those PNR's have internal notification systems which notify the TA (and the employer if the employer cares) of every ticket change, upgrade, SDC and so on.

OP - It would be helpful to know if the customer here is an employer or simply an acquaintance.