Depends what you mean by reprogram. If it was a key that was missing when the last pairing was done and is now ignored by the LR3 as a result, then it can be re-paired by someone with Faultmate or possibly IID tool in addition to the ever friendly dealership.
If he bought the fob of eBay as someone else's spare then he's probably SOL as the key is programmed to the VIN #. If he bought it off eBay as a "******" key then he's also probably SOL as it won't have a VIN # seeded.
In my experience you can't work around getting the key itself from your dealer by providing them with your VIN and getting the key from the UK. You *CAN* save the (in my case) $120 programming charge to "enable" or "pair" it to your vehicle once parts department hands you the new key with one of the tools I mentioned. Took me 5 minutes with my Faultmate MSV2. The $120 I "saved" went towards the "almost paid for itself" fund.
By the way, BBS have a new piece of kit being launched called the Nanocom Evolution for CANBUS (so LR3 and soon LR4) which will NOT be VIN locked. I believe they are running a discount in December - see
http://www.disco3 dot co dot uk/forum/topic88934.html You will have to reconstruct the URL as this stupid site insists on mangling it unlike any other I have visited....
I am not affiliated with BBS other than a customer using the MSV2 kit.