Mark has made a good suggestion, mirrorless can be a really good way to go, but I want to point some stuff out. Now I love mirrorless; I'm drooling over the Sony A7 system and I would love to buy into the Fuji X-Pro system, because oh baby is the X-Pro 2 a sweet camera and those lenses are fine . But don't think that just because they're mirrorless they're cheap. The good mirrorless cameras are just as expensive as prosumer DSLR's, sometimes more (A7R II). It's also important to consider the lens system you're buying into, how much you're going to expand you're gear, if you can get any specialty lenses you might be interested in (this is a huge advantage of DSLR's).
Another caution about mirrorless: be wary of sensor size. You want at least an APS-C size sensor. I have a Fujifilm X20; it's a fun camera, great for shooting on the street, but it has a really small sensor. This means it has garbage low light performance, which either forces me to be creative, or just ruins shots. I'm hoping to replace it with a larger sensor camera (hence my coveting of the the X-Pro 2).
Last thing. About Mark's comment about only specific professionals needing DSLR's. This is a bit misleading. While a few professionals are switching to mirrorless, the vast majority are yet to convert. Mirrorless cameras just aren't yet reliable enough for a working photographer. It doesn't matter how nice the image looks if the camera only behaves perfectly 90% of the time. Also, battery life is pretty terrible on all mirrorless cameras, or at least the ones which attempt to market to professionals.
The take away: mirrorless is great, and I think your friend should consider a mirrorless system. But a good mirrorless camera is not going to be way cheaper than a DSLR. Mirrorless or SLR, they're all just cameras. Consider the merits and weaknesses of every camera you're looking, and the systems as a whole, to see what will suit you best.