besides pintails advice I would
when it comes to defense from a violent person , the victim typically has to be the person to do it , sad but true
so build the story on paper this is insurance down the road
all doors locked on the house all times even when home, we had a crazy lady walking into peoples houses and taking baths , while she was mostly harmless it just proves the point the fastest way to lock a door is to have it be habit every single time you close it.
I trained my daughters on this years ago and yes it is a little frustrating I get locked out as I am carrying groceries in because they walked in the door 10 feet in front of me.
install surveillance cameras , get around the house all angles so you can see everything from inside
sounds like newer house so I assume attached garage , clean it out so she can back in , yes back in this way you are able to open the door , see in , turn the car around and back in so you can see out , then close the door and exit the vehicle.
if you need to leave you are pointed out already and get no surprises backing up
then close the door before you pull away Assuming newer house and automatic garage door opener/closer it is down 3 seconds before you start to pull away.
if you go down there you are mostly there to watch the kids to facilitate the next items
she needs to go to a range and take some training and find the gun that fits her , one she will carry on her and use , if she won't do that then skip that step.
ask the trainer for drills for this type of situation maybe you find the trainer and ask them the questions
there are a lot of types of shooting and she needs to learn up close defensive right now , tactics like turning weak arm into and attack to push off while firing form retention
blue gun (inert training gun) practice knowing what to do and having it as muscle memory are two different things one takes though , the other is reaction with the only thought being do I or don't I pull the trigger.
obtain a CCP/CCL if they take a long time , where she is at , as part of the restraining order the judge can typically issue one.
she is building the paper trail and the skills should they be needed.
you can pay for things , you can watch kids , you can facilitate , but you can't be there all the time and neither can her husband so you are both around for relief and not the fight most likely should there be one.
inform friends , neighbors , relatives in the area , provide them a picture , description, a brief statement of the issue and the police number for her department to report if they see him following her.
develop some code phrases to use for situations
cops often have these little codes with their families , could be something as simple as "I left my pen in the car" and that is the code for let go of the shopping cart we are walking or exiting the store now. just a follow me we are moving
errands and shopping may have to become something your son in law does or goes with on more often
many stores now offer the curb side pick up this might be an option when she needs supplies , but buy some extra groceries ahead so that you don't have to just run out for a minute.
if she has a friend to shop with , it is at least a second set of eyes but they should know what is going on and be informed.
he likely wants her alone or that would be his greatest opportunity to do something
so for a while she can only be alone or distracted when behind a locked door
the situational awareness codes Cooper came up with are still relevant
here is a bit of a description
https://www.cmagriffin.com/situational-awareness-level/you , friends , husband want to make sure she gets enough "white time" it is exhausting to be on all the time that is why the other tools help secure the perimeter for "white time"