Credit card processing + capture data

[RBDude]

I'm doing some research for a friend. He has an app need to process credit card transactions (plenty of apps which do that) but also, upon provided customer consent, he would like to capture their name, address, etc (not credit card into) so that it can be stored for later marketing and contact purposes. Most card processing apps I've seen appear to (by design, I'm assuming) NOT allow the capture of such personal information.

Two questions:

1. Obviously, security and privacy are concerns. Should I discourage him from even pursuing this route?
2. If the answer to #1 is not "no," any recommendations for apps which provide that capture functionality?

Thanks!