First, yes all V70's are interference engines. The timing belt should be done ASAP if he buys the car unless it can be proven that it was replaced. Not sure of the interval for 2007's but I believe most are 105k intervals except perhaps for the early V70's (98-2000). The water pump is optional as the water pumps typically last longer than on the RWD cars and are normally changed at the second timing belt change. However, with that many miles doing it as well should be considered.

The early V70's (98-2000) were built on the same platform (P80) as the 850 series. Basically, an updated 850. The P2 platform is larger and ran from 2001-2007. The 2004-2007's are generally recognized as the best of the P2's.

Is it a turbo or a NA engine? AWD was also available but probably only in the XC model. Turbos should be bulletproof. If maintained, the engine should be too. Parts that should also be checked out include engine mounts, CV joints, front suspension. Take a look at the radiator and condition of antifreeze and tranny fluid. Don't need to tell you that changing all fluids is a good idea too...:)

If he buys it, those engines do best on synthetic motor oil. If conventional oil is used the valve seals can leak at high mileage. I used conventional in my 95 850 (essentially the same 5 cylinder engine) and it started to smoke at about 230k.
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Will I buy another Volvo??? We'll see....