Let's see what others who have obtained a Thai Visa in Vientiane say...
The website has said 5 to 10 business days, but recent reports are that the Thai Embassy is very busy with their workload of applications being submitted.
You may have to show PROOF of your DTV Visa to airline staff on check-in for your flight ✈️ to Thailand...even to the connecting airline staff. Or to the land border crossing entry Thai Immigration Officer.
Upon arrival into Thailand, show the DTV visa to the Thai Immigration Officer and look at the STAMP placed in your passport to be sure you are STAMPED in for 180 days.
Suggest you change the purpose of getting the DTV visa. Likely will be DENIED. Read other replies regarding Medical Treatment plans needed for documentation.
You Only need the 60 day Visa Exempt Entry Plus one 30 day extension { 90 days ...for what you say you need for medical care.
You may have to show PROOF of your DTV Visa to airline staff on check-in for your flight ✈️ to Thailand...even to the connecting airline staff. Or to the land border crossing entry Thai Immigration Officer.
Upon arrival into Thailand, show the DTV visa to the Thai Immigration Officer and look at the STAMP placed in your passport to be sure you are STAMPED in for 180 days.