Hi I own a 1998 Desiel Freelander.
These are acutally quite nice cars for daily driving around and light off road use. (as with any vehichle know your limits and the cars and you will be fine).
The 4 cyl Petrol models are know to have the head gasket let go at random. some have had three in a row go while the dealer was testing having replaced them.
The desiels are good with few specific problems. there are two types of desiel the old 2 litre rover desiels in teh early models and the BMW TD4 in the later one's. (TD4 is the most common in Austas the early models are mainly the petrol 4 which is bad). If you can find a V6 petrol they are quite good with few specific problems. but LR only sell the TD4 in Aust now so they are hard to find.
AS for problems well yes they have some drive line problems mainy with the IRD i belive. Also there are some electrical glitches but most are just stupid littel things that do not affect teh car day in and day out. But generally if the car does not have problems it is fine. if it has problems it is a lemon and will cost a fortune to try and fix while never getting fixed.
As for accorories they are out there and can be found. Not to many companies sell the gear but if yopu put the time in you will find the stuff. Again most of the really good stuff is from either the states or UK so you get stung for shipping. As with anything LR if you by from the dealer you will pay dealer prices for it.
As for making it more off road frendly there are two companies that make lift kits for it one is an Aust company Ironman who make 1.5 Inch springs that are considered one of the best mods you can do to your Freelander as they also help stiffen the ride when cornering (i can tell you they corner well but this helps make it better).
Interior space is very good for teh drive and passengers. I had 5 big guys travel from Penrith to Newnes in it and every one was comfortable. Lugge space is a bit small for my liking but it is a small 5 door softroader.
Hope this has given a bit of help for your mate. other wise get him to check out
Muddy Oval it is a big freelander forum fron the states which will have any info he needs.
Sanzy