Do you think nightmares/dreams and sleepwalking could be connected to illnesses?

Right so this is gonna be kinda long to read, so bare with me. When my brother was little, from the age of about 4 right till he was about 14, he would have terrible nightmares, I remember waking up to him screaming, crying.. everything. He would always sleep walk too, we had a bunk bed but he would always manage to climb down the ladder, and walk around the house doing extremely weird and dangerous things such as pulling knives out the kitchen drawers, opening the front door, going into the back garden… etc. He also has Huge problems with getting up in the morning, like me and my mum will wake him up, and he will get out of bed, and 5 minutes later we will go back into his room and he will be fast asleep again and not remember being woken up.. 2 years ago he was diagnosed with epilepsy, after having quite a few ‘seizures’. a lot of people have been saying something could of happened to him when he was younger, like a bad bump to the head, causing his brain to react differently, causing bad nightmares sleepwalking, and now seizures. My brother is almost 19 now and he takes tablets for epilepsy and hasn’t had an epileptic fit since he was 17 but he still struggles to get up in the morning.

So, do you think they could be connected? sorry its extremely long x_x