Indonesian generally leaves nouns unmarked for number. Context shows whether it’s singular or plural. To be explicit, you can:
Yes. Indonesian word order is flexible. You can say:
• Di rumah sakit, dokter membantu pasien.
This version emphasizes the location.
Either add Apakah at the start or rely on intonation:
• Apakah dokter membantu pasien di rumah sakit?
• Dokter membantu pasien di rumah sakit?
Use the passive prefix di- on the verb:
• Pasien dibantu oleh dokter di rumah sakit.
You can also drop oleh in informal contexts:
• Pasien dibantu dokter di rumah sakit.
Yes, you can topicalize it:
• Pasien, dokter membantu dia di rumah sakit.
This makes pasien the theme/topic, though it adds dia (“him/her”) before di rumah sakit for clarity.