Afraid, I'm very, very sorry to hear about the loss of your mother. I'm sure your father is very lost right now. Do you know if he has friends in the area that could check in on him when you are unable to be there w/him? They were married a very long time and it's going to take a lot of time for him to adjust to your mother being gone. I am glad he has you and the grandchildren to focus on this summer. Your visits will definitely help him. Give him plenty of space and time and if he wants to talk, listen and validate.
About your h, I'm surprised he's back, but his emotions will run high. Keep your expectations at zero and realize it's not about you, but about him and what he needs to do to heal himself. Depression in men is different than in women. Just give him a wide berth and let him lash out and argue w/himself.
As for you, yes, you do have a guardian angel watching over you. Your mother is there to listen and comfort you each and every day. Talk to her, for talking to her will bring you great comfort.
Please take care of yourself. Come back when you can to let us know how you and your family are doing. My thoughts and prayers are w/you and your family.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
