I am not sure what the building code is in Colombo but in Florida the steel in a house is a fairly good Faraday cage. The footer steel is tied to the steel in the grouted cells and that is tied to the tie beam steel. The straps over the trusses is hooked under the tie beam steel.
It sounds like that is the path he is talking about. The lightning blew a hole through the roof sheathing to get to the truss straps.
