Man you've had quite the journey! Cycled water isn't really a thing. The beneficial bacteria you want live on your rocks and substrate mainly. That water from your dad's friends tank may just make the problem worse since it likely contains nitrates and phosphates. Your best bet is to get some distilled water or some R/O water, (or premixed saltwater from your LFS or petco) mix the proper amount of salt into it and do a water change. And the bast way to do a water change is to remove X amount of water all at once then replace said water with your new mixed water. Try to match the specific gravity and temperature of the existing tank water. Hope this helps.
