broken concrete cause of basement leaking?

I'm trying to help my dad out with a problem. All walls of their basement are getting water coming in. A company came out and did a trench drain deal inside along 2 walls. It cost about $3k and would be another 7K to do all walls. (they only did 2 cuz that's all they could afford) My concern is he has a large chunk of his driveway that cracked and is pointing downward by several inches, maybe even about a foot right up against the foundation. Out of the 2 companies he's consulted no one mentioned that it was an issue in the basement leaking. I'm trying to convince him it probably is a huge issue, am I wrong? Just want to say the house is 8 years old, graded perfect from what I can tell, gutters don't leak, has a sump and supposedly was tiled below the footings during construction. The very close neighbors haven't had any issues. He does have a hairline crack in the floor. I know this is really a hard one to speculate on but thanks for any opinions!