I'm concerned my mother's health and care is in jeopardy due to her husband (my step-father). Seeking some advice.

My 72 year old mother has been diagnosed with spinal stenosis and is awaiting surgery. She has also started struggling to "find the words" and thereby heavily relying on my stepfather to finish sentences. Since my sister and I live in other states and see them only 5-6 times per year, we recently had the opportunity to discuss the situation on a family vacation as my mother's recent decline has us extremely concerned. We are worried that this communication issue is extremely urgent to diagnose and inquired why this hasn't happened.
We expressed the desire to be involved in our mother's care and kept in the loop regarding doctor visits, diagnosis, etc. During this conversation we expressed that we would like to help both of them. We explained that caring for another person can be overwhelming and offered to come to town more to help around the home, go to doctor appointments, run errands, basically anything to help ease the stress of becoming a caregiver.

My stepfather explains to my sister and I that we are the cause of her communication issues because we make her "nervous". She is terrified she is going to lose us - which has never been a possibilty. We expressed our love and concern to them in the most genuine way, and expressed desire to be a support system. Step Father replies "my kids are our support system" which was shocking considering we've always been told WE were his kids too.

We ended that conversation and met for dinner. At dinner, my mother went to the restroom complaining of a stomach ache, my sister followed. My mother preceeded to virtually pass out, have diarrhea and become unresponsive. My husband was witness to this and we decided we needed to call the paramedics. I inform my stepfather who is back at the table that the paramedics were called and was told "that wasn't my f****ing place to make that decision" and basically went berserk with anger that the paramedics were called. He then went in the bathroom with my mother alone and only after repeated attempts by paramedics to enter, opened the door, acting like he was unaware that they had been called. He informed my sister and I that it was our fault that she was in this state. We later were told she had been constipated and asked for laxatives which my stepdad gave her. When paramedics arrived, her blood pressure was critically low and she was dehydrated. She was transported to the hospital and admitted.

There is much more to this story, but my basic question is does it seem odd that he wouldn't want her to have the attention of the paramedics when clearly she needed it? I worry that situations like this may have happened in the past and he has dealt with them alone, not informing us or doctors.

I'm very new to the world of an aging parent with health issues and just need to be sure that my mother is getting the care she needs. Thank you for any advice.