If your antenna is hit by a negative stroke, the impulse current is usually lower than 5000 Amperes, although negative strokes can reach values of up to 25,000 Amperes. A good lightning protection system can survive this stroke without any damage, although your antenna and coaxial cable can be damaged. Devices like the MT Isolator are built to lead such a discharge to earth if it is connected to a good, low impedance lightning ground. There is also a positive stroke. This main lightning stroke is extremely strong and the impulse current can reach values up to 250,000 Amperes.
Nothing can withstand such a lightning bolt.
Antenna wire, cables and metal masts will simply vaporise or melt. However, even during a positive stroke, a good lightning protection ground stops the lightning from coming into your house. Fortunately, the positive stroke is not very common.