In Thailand, children under 18 years old are not subject to fines or bans for overstaying their tourist visas. While they may receive an overstay stamp in their passport, it doesn't typically lead to any further penalties or restrictions on future visits.
60 day visa exemption stamp on arrival, 30 day extension for ฿1,900 THB at your local Soromor (immigration office)…that gives you 90 days 3 months
Border Bounce to neighboring county or wherever for an additional 60 day visa exemption stamp on arrival back into Thailand…you now have 5 months in Thailand…but wait there’s more…you can also get another 30 day extension for ฿1,900 THB at your local sotomor(immigration office)
This will get you 180 days or 6 months in total
For the haters…life happens and plans change that’s why I put the additional 30 day extension in my response