iPad Pro Mail app closes when sending email in full screen

I am helping a friend with Mail problem that seems unique to his device.

He has an iPad Pro 11" M4 (MVW33LL/A) at OS 26.5.

He has two mail accounts set up (iCloud and Gmail).

Anytime he sends an email, the Mail app closes. No messages. It just closes.

Sent emails are sent (and received).

It only happens when the Mail app is in full screen mode.

I tried a bunch of things (with full power off/on after any changes). None of these resolved the issue.

I removed his Gmail account (leaving only iCloud).

I deleted and reinstalled the Mail app.

I turned off iCloud mail and redid the Gmail setup.

I tried various "Undo Send Delay" settings.

There is nothing in unsent mail.

The iPad has WiFi and cellular connections and I tried with one on and the other off.

Even with both off, as soon as I hit send, the Mail app closes (on restart of the Mail app, the email then shows as unsent).

I have a 9th gen iPad also at 26.5 and mine works fine.

I thought to do a full reload (restore from a backup) but maybe someone has another option given it's only the Mail app that is problematic.

Suggestions?

Thank you