What’s your role in the unit? If you are a unit admin or one of the unit Key 3, you may be able to look a bit deeper for diagnostic information.
I’m assuming that the email address you’ve been trying is the same as what’s on the new scout application from when the scout joined your unit.
Can you see the parent in the scout’s connections? If so, what is the email address listed there. It would look like this:
That email address should be the username of the account connected to the scout (and should be where the parent received the “forgot password” email). Take a look at the parent’s profile under “Edit Profile” (same screenshot as the email listing) for their BSA ID. That might help with making sure you have the right account.
Also, in the URL browser of that parent’s “Edit Profile” screen, there will be a segment that starts with AdultUserID (different from the BSA ID). You may want that number, since it is the parent’s account database index (of sorts) in the Scoutbook database. It’s often helpful in resolving issues with accounts to be able to identify the specific account, in case there are multiple accounts with the same (or similar) names.