Falls Down While Walking. MRI Scans Normal. Suspecting Nervous Weakness. Suggestions?

Hello Doctor, My father (Age 70) looks healthy no other issue except he falls down by walking, weekly twice he is falling with unconscious, we are worried and tested all MRI scans for knee and whole body MRI Scan, doctors also surprised how he is falling down. Recently we visited another doctor he also suggested to do all the MRI scans and we did the same, and this time they tested for nerves weakness, and they finally found that due to nerves weakness he is falling down. While eating also he coughs a lot due to food stuck in neck , without liquid he unable to eat. Please suggest what medicines he need to take for improving nerves growth. NOTE: Weekly once he takes an alcohol one or two peg that’s it no other habits he has.