I'm not entirely sure about the contents of the medicine bag, as I'm simply not qualified to guess correctly on the given information. I might have some solutions that could work for ending or banishing the hex or curse, however. Though, as a personal disclaimer, I suggest you proceed with my advice under the guidance of your own morals, values and ethics as my suggestions can be seen as more dangerous or otherwise unappealing depending on the person. Please do be careful, whatever you decide.
From what I've read and the information you've provided, my advice to you would be this: If you have a magickal mirror, place it standing up in a bowl of black salt. Those two things are used in hoodoo to shield from negativity. In the bowl facing your magickal mirror, place something that represents the one who hexed your friend/friend's family. This item can be anything that relates to them; A photo or trinket of theirs would work best but a small doll would also work. If none of these items suit you or you for some reason cannot get or craft them, then doing something as simple as writing the person's name on a piece of paper would be sufficient. The idea of this little "ritual" is the reflect the negativity of the person who hexed your friend right back at the person.
As you might have guessed, you can also use the doll for poppet magick. While it's generally seen as a harmful item it can also be rather helpful and defensive. If you were to create a poppet to represent the person who was hexed, you could charge the poppet to take on the damage that was placed by the hex - thus fixing the issue easily without inflicting any harm on an actual being. The trick to this is constructing the poppet and making a spell for the task.
If both of these solutions do not suit you, then perhaps using talismans or binding might be more your style?
A person who is hexed could take a purifying bath, which would then usually free them of the curse or hex since the oils and things used would drive out the negativity of it. The general ingredients are usually things like certain protective herbs, salt, and so on. I'm sure you could find a full explanation of a purifying bath somewhere on this site or perhaps through a deep researching on google. An uncrossing spell might also help if none of those do it for you, though I'd personally just burn incense with purifying ingredients similar to the bath water. Also, creating a protective item such as a talisman or amulet made specifically for spell-breaking could also help a person, but that's for people who have the know-how to do so.
I'm sorry if none of these ended up being helpful, but I do hope you find a solution and help your friend and/or their family.