I don't think the ceiling could handle the weight when someone sits on it. Unless you actually go up through the ceiling and tie it to the support beams I doubt it will hold.

It would have to be bolted through the drywall to rafters, or to 2x4s nailed between rafters, above the ceiling, which can be done by someone who knows how.

Yes it is possible, there are various very affordable hammock fixing kits available online to make hanging a little easier, some of which allow you to hang a hammock or hammock swing chair from a ceiling joist, namely this one for hammocks: http://www.west…
Or for hammock swing chairs:
http://www.west…

There are also hanging tips available on the same site: http://www.west…