Why can't we be closer as an extended family without setting each other off?
Good question, Mike.
Family dynamics are complicated. Family members are intimately familiar with each other and as one reaches middle age, grudges and resentments from the distant past can still color familial relationships. Aging parents can become difficult, siblings and in-laws can become jealous and manifest it in unpleasant ways. Of course, as we age, some folks find themselves disappointed with their lot in life and express it with pettiness and bickering at family gatherings. Just because two people have the same parents does not make them compatible, as you know. Also, as we mature, we all tend to become 'set in our ways' and don't appreciate other family members telling us what is wrong with something we say or do or making divisive remarks intended to belittle us. Family relationships are always a source of strain except in rare cases. Psychiatrists make a career out of attempting to help folks deal with their family. Yours is likely no better or worse than most.
I'm glad you were able to visit your father with your siblings but now that the visit is over I would put it behind me and, as you stated, next time, visit your father solo.
Jim