Since my dad passed my mother's health has declined. Any advice?

Queen Elizabeth was with Prince Philip for about this length of time. It’s said that she died, finally, of a broken heart.

(((((((((((((Hugs))))))))))))))

It's so very common when couples have been married as long as your parents were, that when one dies, the other follows shortly thereafter. Of course she wants to be with her husband. Why wouldn't she? He was, like you said "the love of her life." I find it oddly romantic and very sweet.
My second mom lost her husband of 63 years in March a few years back, and she seemed to give up and went to be with him a few months later in May. No one was shocked or surprised as they were so close and neither would have wanted to go on without the other.
I know it's hard on you, but be grateful that your parents had such a sweet love story. We don't hear much of those anymore these days.
God bless you and your family.

If you're a caregiver, there's never going to be a chance to grieve one parent until the second one goes, too. I, too, never got to grieve my dad, because Mom's needs were right there front and center, and she, too, was crushed by his death. I had to wait almost three years to grieve both of them.

A geriatric psychiatrist will know how to address this, and can also help you with your questions about how to help her address her loss.

We have seen many local grief/caregiver groups appearing since the COVID pandemic began, and it might be a good thing for you to seek one out for yourself, and there are similar groups for young teens. Please be sure your son has some extra support for his feelings. Have you contacted his school to let them know what’s happening at home?

This is one of the hardest situations a Loved One serving as a caregiver winds up having to endure. I salute you, and mourn with you.

So sorry this is just a lot. Your mom is likely depressed due to the death of her hubby. Bring her to the doctor. Good luck!

I’m so sorry for the loss of your dad. This must be so hard for your mom and your sweet son as well.
I think I would get mom to her primary and ask they give her a complete checkup. She may be well but she might also have a health issue that could be helped.
When you mentioned heartbreak I was reminded of an old auntie who went to bed and was crying and saying, “oh, my heart, my heart” when her husband died. They were always devoted to one another, had no children. She called him sweetheart and he called her wife. Years later she had to be in the hospital and the doctors said that her tests indicated that she had a heart attack but that it wasn’t recent. We all thought of how she was when her husband died. It never occurred to us that she had a heart attack.
Perhaps your mom would benefit from an antidepressant for awhile to help her through her grief.
I am sorry you have not had a break. All of you must take care and give yourself time to recover. It is early days since your dads death. Your parents were very fortunate to have you and your son. You have a lot on you. Take extreme care. Big hugs.