The VISA is valid for 90 days from the day it is issued. You must enter Thailand within this 90 days. Once you enter, the visa will grant you a 90-day period of stay that starts from the day you enter Thailand.
Corruption has nothing to do with it. The reason all of this is happening is because a new law came into effect that requires banks to be responsible for all fraud and scams. They are not willing to lose any money, so now they are doing everything in their power to limit their liability. Hence all the trouble people are having now. The big Bangkok Bank thing in Pattaya was just a coincidence.
He would need a Thai bank account in order to apply in Thailand. If he already has that then it shouldn't be an issue. If he doesn't have that yet then he likely will not be able to open it if he enters as a tourist.
Also, she can enter on her expired passport, which is a better option than entering as a foreigner and then being seen by the law as a foreigner subject to immigration laws.
That may have been true 5 or 10 years ago, but it's certainly not now. You'll be stopped and eventually denied entry after 2-3 times trying this. If you want to stay long term in Thailand, you need a long term visa.