Part of the ceiling is bulging and has a small crack.But no water leak coming from the roof. I guess you would have to cut out that section and add a drywall sheet

Looks like a truss maybe cracked. Need to go into the attic to check.

Do not have an attic. Possibly Tape Joint cracking

If the tape is bulging that much, there is another reason than a loose tape, particularly with a crack. Flat roof or gable?

Flat Roof

Too much damage, if a flat roof. Is this someone else needing your help, pastor? This would be a major reconstruction. Best to tell them to find the money to get it fixed. Otherwise distance yourself. I have a flat roof on my garage. Found someone to fix a membrane over it, guaranteed for about, maybe 30 years. Don't know if that is an option in your area. It cost me 800/ CDN