Examples I've witnessed my dad do to my mum
Saying something then denying he said it
Not telling her something eg that he'd made an appointment for a repair in the house but then claiming he did tell her
Moving her stuff so she thought she'd lost keys etc when she has specific places she puts things so she doesn't lose them
Eating/drinking/using things she bought specifically for herself or someone else and then denying doing so and hiding any packaging - additional stirring if it were something mum had been asked by someone else to get and making them think mum had forgotten or eaten/drank/used herself
Cancelling appointments/arrangements she made for no reason and not telling her
Telling her the wrong info for appointments deliberately
Telling her people had said nasty things about her which they hadn't
Throwing out letters about important appointments/arrangements so she ended up missing them
By a former boss to me:
Not passing on phone messages or passing on incorrect info
Deleting work I had done on the company network
Changing work I had done so there were errors in it
(Towards the end of my time there I started emailing completed work to my personal email as a backup which was against company policy but I felt the need to protect myself)
Throwing away my cups of tea and putting the mug back on my desk but denying even being near my desk
Moving trivial items about on my desk so I struggled to find them
"Losing" files to make it look like I'd misfiled/lost them (again towards the end I enlisted a willing colleague as a "witness" to when I put a file back in the cabinet, also she witnessed that the file contained full content)
Agreed days off and didn't record them then claimed I just plain didn't turn up! (I cottoned onto that one pretty quickly and didn't bank on a day off unless I had both electronic and hard copy confirmation. At first I thought she was just "flaky" on stuff like this)
I left eventually things if you can believe it got worse than this and one day I basically snapped and took all my personal stuff and I never went back.
Hope you can support your friend to get away from whoever is doing this to them it's fucking horrible!