You'll be arsed to do it, but it's certainly possible.
Suggest you choose a Bangkok Bank branch near where you'll live because in the long run, it'll be convenient as you can only do many things at the branch where you've opened your account.
Bangkok Bank at EmQuartier near Phrom Pong BTS is reportedly easier than most. Pop in with your passport to obtain their current requirements list.
Obviously tell them your purpose is to obtain a visa and straightaway you'd like to transfer in the required 800k baht. They may 'ask' you to buy an real insurance policy as the staff gets a bit of commission from that, (allegedly) 🙃 555
Siam Legal solicitors can assist you, charging around 5,000 baht; but with diligence; you'll get it done.
The hospital may be able to assist him for a special visa... and/or he can consider the visa for medical reasons
Please enquire at the Royal Thai Embassy in the country of citizenship.
Or better / easier to just apply for a 60 day tourist, which can be extended once adding another 30 days. After that, usually one must leave; so not sure if hospital can have a say in his extending without leaving LOS...