Toilet Ceiling Leaking

I live in an old 1960s apartment and I noticed in late December that water was leaking from the false ceiling in my toilet, right above the toilet bowl. Became worse 2 days later.

Called NTUC Home Income services. The contractor came 5 hours later and sliced the false ceiling.

He said it was bad. He found the concrete dislodged. The steel bars are exposed. Water is dripipping from the steel bar area.

The owner above told me a tenant is living above and he is overseas. He had renovated the toilet last year!

Anyone knows what are the next series of events I should expect? The false ceiling would have been hiding what was going on with my ceiling for months.

I am thinking that their toilet floor and bottom wall tiles (20 cm) have to be hacked off. Toilet bowl, sink all have to be removed. And a contractor needs to apply the water proof membrane on the whole floor and 20 cm of the wall tiles. The whole process may take 4 days.

Should I alert the owner that her tenant would need to find an alternative place to stay for 4 days otherwise he will not be able to use the toilet and bath?