Why am I having nightmares with the same story?
Christian in Jesus
It always starts out with this question, "do you have pets? specifically dogs." With all that drama the property is infested with draco arcon. That is dracuniasis and ascarias water contamination form the urine and feces dogs. jIt is a brain parasite that results in myocerebral infracture (brain death). So it is hidden in plain sight, however everyone is to sick to recognize the problem. Yes, it will follow you because you are sick from being around animals that prey on you using parasites. Get rid of the animals and begin cleansing your body of the rotted waters. You are dying and no one will tell you because they are all too sick from the same thing. Use the source to begin living.
If your grandma, inadvertently or not, is involved with the occult/spiritism, she might be the "bridge" for the telepathic nightmarish attacks you have been undergoing. They´re from demonic origin. Neither you nor your grandma should have any items related to the occult/spiritism. They have to be discarded. Strengthen your faith by studying the Bible. It is a stronghold against the demonic influence. Pray to God, in the name of Jesus, using God´s name in your prayers, and be specific about this problem. More on the link https://wol.jw.org/en/wol/d/r1/lp-e/1102005140?q=spirit+creatures&p=par
The dreams mean it is worrying you as you don't know the solution. I am surprised the medium pointed the demon out but was quite happy for you to live with it. - Unless they asked for cash to remove it for you. There are many charlatans that do this and work this way. Always be cautious if cash is involved somewhere. It's like getting a free roof survey and wouldn't you know it you need a completely new roof at the end of it. I would start out seeing if there is really a problem at all by keeping a spook diary. Write in it anything you think is paranormal or unexplained going on. If there is a lot or things that upset you then ask a local ghost hunting group to investigate - free. You can provide the spook diary as a list of previous activity that will help. If they find anything bad then you can have the house blessed -free, or you can contact a witch which can have the same effect. the witch should also be able to tell you what exactly the problem is rather than just a blanket ceremony as a cure-all. You may find that there is not a problem at all, and whatever is there may just be a passed relative that does not need banishing if they are happy to be there. Not all spirits are bad or need to be removed.
Stop going to Grandma's house