You will have to go to court.
It depends on local legislation.
Up to and including death depending on the cirucumstances
Indiana does not have gun registration. If you're carrying your firearm in the legal and prescribed manner, there is no requirement for it to be registered.
packing
Yes
only unconcealed
to protect himself
packing or loaded
Laws on this vary by jurisdiction.
If you are carrying a gun and your license to do so is not in order, you will be arrested.
You will have to define what you mean by carry, and which gun. There is a large difference between carrying a concealed handgun, and carrying a rifle or shotgun when hunting.
If he allows you...both of you can get in very serious trouble. It makes no difference if the gun your carrying is stolen or registered to someone else. You have no right to posess it.