Sorry to hear your dad is having a tough go of it. I empathize with him. I was a self-described 50 year-old "tough guy" before I got sick. It was quite a shock to me, not only physically, but pschologically, emotionally and spiritually. I too have trouble with anxiety and insomnia. I take Klonopin (Lorazapam) when I really feel anxious. It helps. It also helped me also to maintain a consistent regimen, going to bed at a certain time and waking up at a certain time. Some nights I lay in bed (reading) for quite some time before I sleep. But this routine seems to be working.
It is so great that he has you helping him! However, it might help if he himself gets "on-line" and researches himself. When I finally joined this forum it really helped my outlook plus I learned volumes!
Good luck and keep us updated on his progress.