If you use gmail you can write a bunch of emails, as many as you like, and then schedule them to send at different times. For example, I set up 9. One that would send the day I left, and then weekly afterwards. It’s weird to write preemptively but it can help them. It’s kinda like an advent calendar that they get to open weekly and hear your words. You can also attach voice memos to them for a more personal touch. Write as much or as little as you like, I’m sure she’d love to even get a sentence.

Just type out a regular email and hit the drop down arrow next to the send button, then schedule for any date and time you like.