Leaky Water Sound 24/7, need your advice.
I am posting this about a friend's home.
He has a row house with a bathroom on the 2nd floor. He can hear a click/leaky water noise(like a popping sound) every few seconds and all the time. When he turns on the sink fawcet or tub fawcet he can hear a fast click/leaky water noise for 30 seconds and then it stops. When he turns off the fawcet, he can hear the click/leaky water noise every few seconds. When he's in the 2nd floor bathroom he can hear the sound inside the walls, and when he's in the next room he can hear the sound under the floor. He hired a handyman to come check it out. under the 2nd floor bathroom, there's a kitchen. He opened the ceiling in the 1st floor and saw the pipes without any leak. Tho this area was not directly under the sink/tub of the 2nd floor bathroom. It was about two feet to the right but he did see the toliet pipes and the main hot and cold pipes, he stuck a metal wire with some towel and moved it upwards and found no wetness. He couldn't find any leak, so he turned off the main water supply. The click/leaky water noise stopped. What should he do? Hire the handyman or licensed plumber to open the sink and tub fawcets and look into the pipes in the wall? that would require to break the wall. There is no water leaking from the ceiling on the first floor, althought there is an kitchen vent with under the sink/tube. Any suggestions from you experts on here? thank you.
Also, Let's say there is a leak, since it's sounds like it's a drop of water every few seconds and then rapid drops of water for 30seconds when the sink is turned on. Over the long term, will this cause any structural damage to the wood beams?
Also, when the handyman opened the ceiling he saw a unused old light color pipe hanging loosey next to the copper water pipe. When he turns off the tub fawcet fast, he hears a clap sound. It sounds like the copper pipe hits the old unused pipe. is this dangerous? Also, he felt a wind draft moving upward. Is this normal? clue