Thanks @Sahara I totally understand your resentment. When people suffer depression others usually don't relate to the suffering as they can for example relate to others whom have terminal illness. And a lot of the time we can become emotionally neglected because of this when ill. This happened to me to and do totally relate to what you are saying.
This resentment can totally cloud things when we help others whom may have neglected to be their for us. My husband who loves me more than life did not have a clue on how to help me when I had a breakdown; when I was severely depressed and anxious. In fact, sometimes he said things that made me worse. Sometimes I felt humiliated (he would say well meaningfully - don't be such a child, your an adult, don't whinge etc). Sounds horrible yes, but my husband is a good man who loves me more than life and has stuck by me through her thick and thin, and would always do his best to try and make me happy in his way. He just doesn't get it. He doesn't understand and that was his way of coping, it is ignorance really but his undying love was always presents, undeniable and got me through.
What helped me to push anger/resentment out when in similar situations that you are finding yourself in @Sahara so bitterness does not dig in it's poison were three helpful aides - a) I put my whole focus on the others situation not allowing my inner pain etc to shadow my compassion, by putting myself in their shoes and empathised to the best of my ability, full focus on the other loved one at that time I am with them - this usually pushes out any anger or resentment at that time (although the pain can come back when I am alone, but not anger, resentment as I let that all go. I worked out that only hurts me).
I would have to do that with full force of will when my mother dies as she was a bad mother, an abuser. I don't see her but if she's needed me at that time and asked I would go and push the rest aside. I wasn't cared for and neglected by her my whole and can feel enormous grief over this. And the longing for her love. That's why I like to keep my mind and body busy as feeling like this is fruitless. And I don't want to be further damaged.
b) I realised it is was ignorance and a lack of understanding on their part and they did not understand the extent of my mental suffering. And they loved me (except for my mother). The latter knowledge of love being there is most important - focusing on that love regardless how flawed. Your parents in their way loved you @Sahara. Keep this on the forefront of your mind when you feel you were not cared for the way you needed to be. That love gives value, even though imperfections flawed it.
A good example of when I felt similar neglect and lack of understanding of my enormous grief and resulting major depression was when I was estranged from my children. Worse than death to me. A lot never sympathised and still don't. But those who have gone through it feel exactly the same (there are many support groups for this in the states - we are behind in that way) It's because they have never been through it and don't understand. Same with depression and anxiety.
And c) I realised my Dad loved me to the best of his capacity (my dad passed from cancer) and he was a good man. So I pushed the resentment and hurts aside whilst in their presence allowing compassion for him in his present situation to come to the forefront rather than my pain. For this moment in time when with him I made it about him, not me. And I am so glad I did. As I sat with him all night whilst he was dying and when he passed, after initial grief period, I felt absolute peace I did the right thing having no regrets.. I felt his presence around me not long after he departed, I felt his love. And it was stronger.
With all your dads faults remember the love @Sahara for you that he has, even though imperfect and flawed. And this may help ease the pain of past neglect through ignorance. I am sure if your mum and dad could take it back they would. I wish I could go back in time and change a lot and make it right. Parenting is the hardest job in the world, the most important and can be the most heartbreaking in my life experience.
But also be kind to you. It is a tremendously hard blow to have only gotten over losing your mum, the grief of that, to only be faced with it again. And for those feelings of "why didn't they care for me more, love me more" being triggered once again. Unresolved hurt, mental scars are hard to carry and can hold us back from our true potential in everything. I try and not allow this and do the opposite to what my pain/depression is saying to do.
Living as if your father is t even sick is your minds way of escaping the pain. Avoidance of grief. But avoidance only makes the reality hit harder when it happens. Best to follow the heart which may tell us what we don't want to do or face but is always best for all concerned it the end.
Feel for you @Sahara In this difficult time, it's not easy - but one positive is that is you are having no difficulty expressing how you feel to others about it here and that is a step towards healing. Well done as expressing suchnis never easy. Sending lots of love, OTE ❤️