Not sure just an exchange will work on that, you'd have to do the bike test. Not particularly difficult though. If you can't pass it, you most definitely shouldn't be on the road. Issue is the back log for tests.
It can be 2 separate things or 1. If you have coverage at home that will cover you in Thailand then you may need the covid coverage separately. If you need to get insurance then you may as well getting all in one. Tune and AXA are generally the most popular ones
he's in an AQ. He signed up for 7 days quarantine. This will not be a shock to him and I doubt it's just a holiday if this is the route chosen. Their frustration is that the rules have relaxed but they have to stick with the original regime
I applied for one last summer and got away with a booking.com booking that was easily cancelable. Maybe theyve tightened things up but I'd say the lack of utility bill with home address is the bigger thing. They want to know you have a home to return to I think. You not got a mobile phone contract? Statement from that should be okay