What does this mean in a dream?

There is not enough information to analyze. Why is your ex still trying to influence you?
Your ex knows your mother dreamed this? Sounds a bit controlling.

What is it you would do differently based on this feedback from your ex?

@78713js Dreams don’t mean anything. You can go on about your life with the same level of risk of death as you’ve always had (well technically if you factor in the global pandemic that’s not completely true—but you take my meaning).

And just for argument’s sake I’m wrong about dreams being meaningless (I’m not wrong though). Let’s say dreams somehow could predict the future. This would imply the future is determined which would further imply that there’s nothing you can do to prevent your death. This begs the question, if you really were a person fated to die in say 64 hours (don’t worry, you’re not) would you want to spend your last 64 hours on Earth wandering around in a state of paranoia/panic/fear just waiting for an anvil to fall on your head? Or would you rather just spend that time living your life?

Get the vaccine, wear a mask in public, wash your hand, wear a seatbelt in your car, and a helmet on your bike, look both ways before crossing the street, but otherwise, just live your life and enjoy it because you only get one.

Dreams mean that the person was asleep. That’s all.

Do not take this crap seriously.

Death dreams usually signify change in the relationship or ending’s, even new beginning’s.

I’d say an ex telling you that means they are likely feeling the loss of you in their lives or are nervous about starting a new relationship.
Are you afraid to move on, or is the ex? Have one of you started dating again? Are there lingering feeling’s one of you is having a hard time with? Was this a fresh break-up?

Or it could be an omen if the family is/are pre-cogs, but that’s extremely rare.

If you can alter your behavior without significant cost to yourself, you might want to consider doing so. Changing things up tends to be a good thing to do from time to time anyway, so why not?

I know many people who have had dreams which have seemed to correlate strongly to something in the near future, particularly in terms of danger for a specific person. Dreams are pretty much always symbolic rather that visions that correspond directly to the actual future.

There is also the possibility that your ex (and/or her subconscious) also knows something that she’s not telling you. Particularly if what you are up to involves dangerous other people.

It could also of course mean nothing, or mean something else.

You have a fear of death, just like everyone else. When your relatives voice their dreams on the subject, your brain focuses on it and you tend to dream about it all the more.
Dreams are not omens about what will happen in the future. They are just the manifestations of what your brain is working on during sleep when it is sorting out the things it/you want to remember.
Don’t sweat it!

Death could also mean an ending not a physical death.