Definitely heed previous posters' advice re medication: best not to mess with prescribed meds but to push them to get reviewed asap as it could indeed be that they are contributing to the problem. Definitely seeking a crisis team referral needed if she's so bad that she can't be left alone - they might not agree to assess her but you never know, and it would probably be the fastest way to get expert eyes on the situation. Highlight any concerns about her safety.
The breathing and grounding techniques that a poster suggested could indeed be great but better to introduce one at a time only, to practise with her gently and make sure it doesn't feel overwhelming. Also good to set expectation that it isn't going to take the anxiety away but might provide a break from it - people often try this stuff and say 'it doesn't work' but that's sometimes because it's been missold to them.
If your mum is able to articulate her worries / sources of anxiety, that would be amazing, but some people can't put it into words. Never useful to try to rationalise someone out of anxiety when they're in the grip of the worst of it. A rule of thumb for anyone in distress is to validate their emotions to show you've listened properly and care about them; gently and firmly reassure (without getting into any sped of logic-based argument), and if possible try to redirect attention to a distraction of some sort (but the latter step isn't always possible). If you have kids, this is sort of similar to what we might do with a little child if they're upset - and I don't mean that in a rude way! It's just the observation that when anxiety takes hold and emotions feel overwhelming, it can be sort of similar to how it is as a little kid: not able to express what we want or need; a deep need for warmth and comfort and firm support.
Crucially, no idea what your mum is like and what she's been through in her life, but most distress is understandable when you know the context (however inexplicable or irritational it might look to an outsider). There is always hope for recovery. And hopefully you and your dad can take care of yourselves and one another through this, because supporrting someone who is struggling takes a toll, no matter how much (or perhaps because) you love them - any way for you to give one another breaks / time away would be good.