You want your mother's read on whether the kids spend August with her, or you keep them home and she visits for a week. She does not use an assistant. She barely uses the family chat. She does read email, in the morning, with coffee, and she will answer one clear question. She will not answer a four-page history of why your brother is impossible.
Ask for an opinion. One. Then stop.
Email and a link are enough
Writing to someone who is not on RelayLink is ordinary email: a short notification and a link to the briefing. Nothing to install. No password. If she later wants an account, that is her choice; it is not a prerequisite for weighing in.
If she already has an account, you need an accepted contact before a send will go through. Most grandparents do not. Do not invent a reason they should sign up in order to tell you whether August works.
You still approve the send. Letting an assistant email someone means the draft is assembled from your session and you read every line before it leaves. She should never receive a paragraph your model wrote in your voice that you have not seen.
One question, two options, why her view matters
Respect her time. Open with the ask: "I want your opinion: August at your house, or a week-long visit here in September." That is an opinion, not a decision you are handing her. You will still decide. You want the person who has hosted these kids for twenty summers to say what she actually thinks.
Give her the constraints a cold reader needs:
- School starts the Tuesday after Labor Day.
- Your brother already claimed the cabin the first week of August.
- She has a doctor's appointment the 12th — if that date is wrong, she will correct it, which is the point of writing it down.
Leave out the novel. She does not need the Slack argument, the weather spreadsheet, or your assistant's ranking of "family cohesion." If a sentence exists to justify you, cut it.
A sufficient reply is a lean and a reason. "August here is too much driving; come in September." That is a complete answer.
Do not make her the referee
You asked for an opinion on August. You did not ask her to settle the thing with your brother. If the briefing smuggles that in — "and maybe you can tell him" — you have handed her a job she did not take.
If she would rather talk, she will say so. Send the written question anyway. The call then has a spine, and you can write down what she said afterward so the next sibling who asks "what did Mom think?" has a page instead of your memory of a Tuesday morning.
She replies from the email or the link. A reply is how you know she has it. A fetched link is not a read. You cannot see whether she has told your brother. When the next holiday question shows up in a session, connect your assistant and send one question, not the family archive.