What reason would make you want to do this? Does he need a T/L on his CR?
Dell may or may not allow you to add an authorized user or they might tell you that all they can do is a "joint account". This means a hard inq. to his CR and then he shares financial responsibility for the account.
My ability to predict what will happen is zero, zilch, nada, uh uh, no way!!! It's not possible, even though you would think that adding a T/L should be a positive thing you would be surprised what happens.
It should report but I have no experience with Dell.
Hope you get what you're looking for
FICO scores on November 17, 2014 (prior to applying for and being approved my mortgage)
EX=738
EQ=735
TU=754
FICO scores on March 4, 2015 after being approved for mortgage and buying the home, the mortgage isn't yet reporting.
EX- 689 EQ- 739 TU- 739