What you described using an agent is accurate.
The bank account is the simple part.
Approx 5k. Most of which is insurance policy cost to bank.
Most likely BBL.
You friend already had a non O previously so agent provided service to cover the financial requirements to obtain 12 month extension.
If in future he wants to change back to DYI then he can seek advice from forum.
I notice that friend had option to change to based on retirement to based on marriage.
The financials are far easier for marriage and can be used after extension granted.
He could have brought time by obtaining 60 extension to visit wife, but that's all water under the bridge.