Questions & Answers about सबको दवा चाहिए।
सब means all or everyone.
The ending -को is the postposition को, which often marks:
- the person affected
- the person receiving something
- the person who feels a need, desire, pain, etc.
So सबको literally means something like to everyone.
In this sentence, Hindi is structured more like:
- To everyone, medicine is needed.
That is why को appears with सब.
चाहिए and चाहता है are different.
- चाहता है means wants
- चाहिए usually means is needed / is required / is wanted
So:
- मुझे दवा चाहिए = I need medicine
- मैं दवा चाहता हूँ = I want medicine
In many situations, चाहिए sounds more natural for need, while चाहता/चाहती हूँ sounds more like a personal desire or wish.
With दवा specifically, चाहिए often strongly suggests need, not just want.