Bless your heart. I am so sorry for your loss.
It's a lovely thing that Adam wants to help and comfort you in this tough time. I agree with Redpepper, it is OKAY (and natural and healthy) to grieve the loss.
I would also encourage you to continue to invest in the relationship you still have while you grieve the one that is lost. Let Adam know you appreciate his love and support. Thank him. Love him. Do what you can to "take care of the caretaker." Make him glad he's there for you, in good times and in bad.