The charge is usually 220 baht, which is hardly eye watering on a 20,000 withdrawal, and considering you've just spent around £1000 on flights. And the rates are pretty good compared to booths outside of Bangkok. For the Cheap Charlie's, 220baht is a fiver.
Nope, and why are you apologising? Most policies are limited to 30 days in country. Some might have other conditions. What you are referring to are non-standard policies. LV will offer a policy for 366 days if 65 and under, and 31 for over 80s, and 90 days in between. On average, standard annual policies are about £80. So-called backpacker polices, on average, are about £140. But the cost will be a lot higher for the elderly, plus there wil be additional policy restrictions, eg the length of the policy.
The expensive bit is medical repatriation, which might be £100-150k. You won't get treated for cancer etc on travel insurance. It's supposed to be emergency cover only, eg life preserving surgery only . If you break a leg, emergency setting, "good enough", but no rehab, andback home, you will face further surgery, probably
Most standard UK travel insurance schemes are limited to 30 days stay in a country even if the policy is 12 months. Specialist policies need to be looked at.
Well, it might meet the monthly requirement, but as mentioned, he needs 800k in the bank, and best not use a corrupt agency. Might not be much of a life if spending £5000 a year, and up, on flights back to the UK.