Hi XX XXXXXXXXXXXX;
This is true. Most likely the removal of the tiles will damage the in floor heating...unless he is carefull doing it.
His best hope is to break up the tile into small pieces and this should allow its removal with out damageing the heating tubes.
Once the tile has been removed he can use a shop vac to remove the broken material between the tubes and then regrout them back in place.
If he takes his time doing this he should be able to keep the tubing from being damaged.
To break the tiles use a masons chisel and a three pound sledge hammer. Use single sharp strikes rather than trying to drive the chisel into the subflooring. The object is to crack the tile without mushing it into the tubing.
Best, THS
Jack of all trades Master of a few.
#1 Home Improvement Expert. Over 30 years experience in construction, and home repairs