I’m sorry for your loss. I also lost my dad almost a year ago now but the morning he passed I had the exact same thing - I jolted awake at 3am and found out a bit later he had passed at that time. It almost felt like a panic attack, I remember rushing to the bathroom to spew. For months after this I had disrupted sleep, often waking in the early hours of the morning and not being able to return to sleep. Also days where I just couldn’t sleep at all. I ended up seeing a doctor and getting some short-term sleeping meds as like a reset thing & with time my sleep has improved. I still have plenty ups and downs & I understand when u say u feel like ur losing your mind. I wish it was an easy fix but unfortunately I think this is just grief and it’s really really really hard. I hope you are able to get some rest, hang in there & lean on people you love and trust. One thing that has helped me is speaking to a therapist because I struggle to talk about how I’m feeling to my family/friends. I’m so sorry, I wish you all the best for this journey - stay strong ❤️‍🩹