Taking a bearing out by heating the engine to 200C will not ruin the bearing.
They are made of STEEL (or ceramic) and will hold up for a much higher temperature than that.
BUT, I would still try to talk him into buying two new bearings (front and rear) unless he has an extremely tight budget
If you are going to re-use the bearing make sure to not use any tools when getting it out and also make sure to clean it very very well.
Some denatured alcohol (do you have T-Röd in Denmark?) and then rince it with lots and lots of hot water in the sink, re-oil it and mount it.