Well, in the first place nobody really got hurt too bad. Your parents marriage dissolved for good reasons and your mother was not doing a good job in it. The marriage your single dad broke into also seemed to be in the ditches, the lady in it not doing a good job and the husband dealt with it up front and straight forward. Even for old folks, this , that, coulda been worse.
First of all, take a pragmatic and wide sweeping approach to things. Wide sweeping, meaning, consider this slog with all the other challenges you face or could face, past present and future. You probably have a lot of responsibilities, dreams and things to deal with yourself. And the world around us, near and far, is filled with serious problems and problems that could be on the horizon.
Third, as parents and people age, a lot of them become pains in the ass, not just because of care taking but declining mental states. They say crazy sh1t increasingly on the road to mental laziness, dementia, and flip flopping from moment to moment. Take it with a lot of salt. This is especially true if they were like this when in middle age.
Try to see the upside in it. When multiple conflicts arose, people got over it and kept calm, as opposed to the poo hitting the fan and a domino cascade of chaos going off, with people completely losing it, letting out all their baggage elsewhere in life, breaking things, committing violence, losing social decorum, sending hate and incitement in other directions, destroying business good names, etc
If you're still feeling conflicted, do some personal writing and try to pursue associations and feelings and get to the source and roots of your concerns. You can also talk with trustworthy and interested yet detached friends, and maybe a decent therapist.