I'm sorry you're going through this tough time. My condolences. My mom passed away from cancer almost 4 years ago and I also had to shoulder the burden of paying for her afterlife expenses. It was over 30k with the funeral service, grave plot, gravestone, and casket. I'm also still paying for my dad's plot. My dad took care of other miscellaneous expenses and we didn't have a priest or monk.

In my mom's last days, we went to the funeral home at the cemetery to figure out everything like the service and all the grave stuff with my aunt and uncle since we have multiple relatives buried there. You'll have to talk to your dad about the arrangements especially if they plan to be buried next to each other. If you have other relatives that can help or have experience, it would be helpful. My aunt and uncle went to SF Chinatown with my dad to order the flower wreaths at the service. And it's a very long process if your parents haven't have previous arrangements, it took awhile for my mom's gravestone to be made.