Go to the local hospital talk to the clinic receptionist ,see a doctor with your paperwork ,get your prescription from the hospital pharmacy pay the fee ( usually just the cost of the meds and consultation about b500-b1000
When need again attend the pharmacy with a copy of their original prescription and continue
Very straight forward min cost/hassle took a pal to Bangkok hospital udon for some methadone ( recovering addict)
I had the same problem with my wife’s sister when we invited her to visit so I took them to an immigration tribunal in the uk proved my ability to support her during her stay and stated we paid millions for immigration enforcement in the uk should she fail to return within the specified time cost me £500.00 for the lawyer in the uk he visa was granted immediately and she spent 6 month here in the uk
Sometimes you need to take it from the embassy in BK you can also apply on her behalf in the uk using your financial status cheaper than an agent who will probably fail and very straight forward to do took apex 3 months
Had to do the same when i married my wife she has now been here 16 years and has ILR
day tourist visa very easy to get a 60 day from the thai embassy all done online takes max 10 days then extend at a local immigration office fee 1900b if you do the paperwork yourself 2000 b if they do it for you will give you 88 days assuming you don’t wait until the last minute to extend
I did mine and two others at Udon Thani immigration office paid the 2000 they did all three extension the whole process took less than 45 minutes if you need more than 90 days the you will need to do a border run for each 30 period you can do this six times (but can only extend once at an immigration office ) meaning technically you can stay in Thailand for a total of 260+ days as a tourist if you start with a 60 day visa. Hope this answers your question obviously if your over 50 their are various 12 month visas that you can apply for based on your income