As always with Thailand it depends on which Immigration Office you deal with. My experience in Hua Hin and Sri Racha was that you need individual residence certificates for; opening bank account, obtaining a driving licence, buying a car etc.
I have seen online that other offices provide a general residence certificate. Also, some offices charge for issuing them (Hua Hin and Sri Racha did), but other offices do not.
very true. I was making it a general response without listing countries individually. I suspect he will want to take her to places like Italy, Spain, France and maybe Switzerland. If he's going to do it he needs to check the individual countries to ensure the Shengen covers it.
I use a Starling debit card and it is brilliant. She can use it to pay for things in supermarkets and shops that accept cards. She can also withdraw money using the card. If she goes into the bank with her passport, there is no fee and they pay the Starling rate of the day and that is usually as good as anywhere.
I also use Wise, but only to transfer cash to my Thai bank account.
I believe that Monzo is very similar to Starling, so maybe get both, just in case anything goes wrong with one of the cards.
also the immigration officer can be investigated and if he's caught, all of the visas he issued incorrectly are cancelled and the individuals are then leaving Thailand. I have seen several posts over the past 2 years where this has happened, so it does happen.
as James and others have stated banks give a terrible exchange rate. Go onto the Wise site ads they have a comparison tool (Wise are not always the cheapest) and compare it to how much you will get from your bank ( I am presuming your UK bank is a high street bank).
I would also get a Starling or similar bank debit card. I sometimes withdraw cash using this card and use it in Thailand as they do not charge fees and give a great exchange rate.