I am really sorry about your Dad.
What a lot to deal with. Yeesh.
If you have any reinforcements....Now is the time to call them in. A bestie, a cousin, an aunt...anyone you trust. You need help.
You need to drink. Sip, sip, sip. This is so important. Keep drinking your clears and keep drinking your protien drinks. Put a couple in your car. Put a couple in your purse. Keep drinking. It's your most important job right now.
You need to rest when you're tired, but don't sit or lay for too long. You need to get up and walk every hour if possible, except when you sleep at night. Don't exhaust yourself, but keep moving.
If you're doing cremation, consider delaying the funeral. My mother in law passed unexpectedly and we did her funeral a month after her death because there were significant health crisis's among the core family. It's unusual, but there is no law against it and people really do understand.
Best wishes, and again, heartfelt condolences.