it's not a normal Desktop case built, it's a Dell OEM so if he changes the case he will be in a hard pain process of Modding and configuration of the case and which will be finally unsuccessful Due to the CPU Cooler, Front Panel, Outputs and the Unique Dell air flow system
the card will fit in the case but you'll have to upgrade the PSU cuz it's 300W which is not sufficient for the whole system / and you'll have to leave the case cover opened as the GPu will reach 100 Degrees inside your case for the inappropriate air flow
So you're saying with his current Mobo and CPU cooler arrangement, he can't find a case that is larger, and will provide better airflow for his system?
( Also, you said CPU instead of PSU )
no mate, it's impossible... i had a Dell machine and i know how their design works... simply he is going to do a hard modd process and it won't work perfectly....
the problem is not the larger case the problem is that Dell measures every inch in their PCBs and accordingly they design the case... it looks like this