We humans normally communicate with one another verbally while awake, and this communications form network of connection with people within our groups, communities, societies. The stronger we relate with another member in a group the stronger the connection. It's a bit like Computer Network or how Computers are connected together globally via the internet to communicate with one another. Now imagine you power down your computer into "Sleep mode" to rest it for sometimes. While in that sleep mode the computer's internet has to be always on to be able to communicate with other computers globally while operating at low power mode. You could say the computer is dreaming in that state. This is somewhat similar to how humans dream while asleep
When we fall asleep we continue to communicate with people who we are connected to. In regards to the connections, imagine you are strongly connected to a love one who is strongly connected to many friends, when you dream about the love one you could also see or feel the presence of the people they are connected to. If you have strong conversation with your love one today, you may actually soon be dreaming about them or about those they are strongly attached or connected to or those they have recently had deep conversation with about you.
Human are well interconnected by unseen networks, similar to how computers and other internet enabled devices are connected wirelessly. But there are only two separate interconnected networks that exist in this human connections, one is Good while the other is bad. The good is basically made of network of people same as the bad. At the center of Good Network (which we could call the "Right side" network) is some sort of Being (a SUPERBEING) that controls it, while at the center of the left side network is a dark entity. It's more like two separate networks of computers connected to two separate Supercomputers. The computers are heavily dependent on the Supercomputers and are controlled by them. This is similar to the human networks. The humans depend on the Beings in the middle of the connections to function.
The computers constantly receive messages from the Supercomputers, like warnings, predictions of things to happen in the future, etc, which are sent out by the One in the middle of the right network to the rest of the computers individually. The computers receive this messages occasionally or regular and use them to plan ahead. Like the computers, part of what humans receive in their dream from the SUPERBEING are warning, predictions of things to come, etc.
There is also a phenomenon that occurs in the dream that can also be explained - dreaming about people who are already dead. You could be communicating with them or seeing them appear and vanish in dreams. Once a loved one for example, is physically dead, the connection with the dead human is supposed to stop, but since the dead has already formed strong connection in your mind while alive something else may take its place, its past could occasionally replay in your dream or you could be interacting with its replica. Let use the network of computers to explain this, if one computer ceases to exist in a network, maybe because it was destroyed, and the owner has backup copy of the computer data, he/she can use the data on another computer and continue to exist like the original one, but the truth is the copy can't be exactly as the original. It could still continue to communicate with the people that had built strong connection with the original computer.
What to do if you do not want to continue dreaming about a particular person
To stop dreaming about a person, you'll need to completely forget about that person physically by avoiding any connection with him/her, and by avoiding anything that has strong connection with him/her. Your connection with that person will gradually fade away physically as well in the dream.
If you want better dreams, connect with better people.
Make sure you are connected with the right people who are connected to the the right friends. Ofcourse, you could ask people you wish to build strong connections with about their best friends or loved ones and possibly investigate things personally to be sure they are people you would want to be connected to or relating with in dreams. I will suggest finding the network of people at the right side and connect with them. They are typically very few in number and hard to find but when you find them make sure you become part of them to have better dreams. If you can't find them, you could do well by starting a good network yourself where people can be taught to be better humans who hardly mingle with the bad side to avoid getting corrupted. Once trained, they become part of the family and share dreams together with you.
It's important to note that you can only form an invisible network with people that feed on thesame information or knowledge you feed on. If people consume thesame things they believe in, they automatically become part of thesame network and controlled by thesame Being in middle of the network who is also the source of what they consume.
Hacking the Dreams
Ofcourse, you are prone to hacking if you make connections with dangerous people, or love ones who are connected to dangerous people. All an attacker needs to do when your defense or firewall is weak is to infiltrate your dream, steal your secrets or inject you with evil things. If you are not attacked by your direct connection, it's going to be indirectly via your best friend's or love one's friends. Assuming it's a computer you are connected to, the computer may be vulnerable if it's connected to dangerous computers.
So make sure you know who your friends mingle with before making strong connection with them. If you are successfully attacked in the dream it's probably a sign something bad could happen or has already happened physically. Be careful who you connect with then watch your dreams improve.