I'm not a contractor, but I've learned a lot from others on this topic, and I've had to deal with water infiltration before.
I'm not sure what measures your friend has already taken to fix the issue, but I would do the following, roughly in this order.
- Ensure that the grading is sloped away from that wall. Go buy bags of top soil if needed and add it to the side of your house to improve the grade. Lay patio stones that are tilted away from the house if you have to. You must avoid pools of water accumulating along the wall.
- Are the eavestroughs in good shape, clear, and functioning properly? Are the downspouts directing water far away from the house? It helps to walk outside with an umbrella during a heavy rain to observe where the water is coming from and where water is pooling. Take the necessary steps to direct rainwater from the eavestroughs away from the house. With the rains we've been having, I wouldn't hesitate to redirect a downspout 15 feet or more away. You can get creative with the downspout path if the property allows. Ideally, having downspouts spill water down your driveway is preferable over dumping water into your backyard, but sometimes this isn't possible.
- If the above two measures are implemented seriously, you should have eliminated most of the water source issue. But sometimes you still get water getting in, so then you may have to break down and dig. I'm not an expert at waterproofing foundations, so I don't want to comment on the actual methods. If you can't get equipment in there, then you may not have a choice but to dig by hand. Of course, this won't be cheap.
(I don't have experience with sump pumps, so can't comment on this.)
Good luck.