Severe Spinal Stenosis Surgery Advice.

My dad has severe lumbar spinal stenosis with nerve compression. MRI shows the nerve tunnel is less than 5 mm, while doctors say it should normally be around 12 mm. A spine surgeon recommended surgery of Adv - suggested Lumbar decomp surgery + fixation because medicines and other treatments have not given relief. However, my dad is following random treatments from YouTube and Facebook doctors who claim surgery is not needed. One such doctor asked for one lakh rupees for non-surgical treatment. We are ready for surgery and even sought a second opinion through our family doctor, but my dad is not listening and has now taken a loan for that treatment. I love my dad and only want proper, evidence-based treatment for him. Is surgery usually the best option in such severe spinal stenosis cases when conservative treatments fail? what to do my dad already tried different doctors and treatments but did not get relief is it surgery is the right option what to do ? i attached reports please check