Roof screws need replacing

Anything is repairable if you throw enough money at it. If you already owned this house having it repaired would be a consideration. A perspective buyer should have the current owner address this or the buyer should get an extreme discount.

A $100 inspection would provide you with a list, containing deserved discounts; the cost to replace bad wiring, plumbing; anything out of order. It's a bargaining chip, where the owner will probably fix what they can on the cheap or eventually agree to a reduced price. 50k(US) is a very rough ballpark for a roof gut, plus.

Being at the wrong end of multiple countries divided by a common language, in the USA I'd be looking for a company listed under "roofing" or "roofers" and preferably one that specifically mentioned metal roofing as something they do. The same people that install them in the first place generally know how to fix them as well.

As a self-described non-handy person, don't try to go up and have a look. If you can look at the suspect area of roof from the ground (perhaps with binoculars, or a long lens on a camera, and then you could post that image here) you might or might not be able to spot something, but in general unless there's something missing (such as a section of the peak flashing) your roofer will go have a look closer to detect the problem area.

The leak outside is often not where the leak inside is - it's usually somewhat (or quite along way) further up the slope of the roof.

AFTER the leaky roof is fixed you (if you care to tackle an easy start to "handy") or a drywall/plaster repair person would need to fix the ceilings, and then they will need to be painted. Often you can find one company that does both painting and plastering, but some specialize.

Be sure the roof leak is truly fixed, first.