Loss of Balance while walking. Problem.

My father is aged about 62 years. He have both Diabetics and BP. From last two months he is suffering with Loss of balance while walking, he is having this issue only while walking. We have gone with full body check-up. We consulted general physician at first and he just suggested some vitamin medicines, later we consulted neurologist he suggested for MRI, both MRI and full body check-up reports are normal, so doctor suggested some regular medicines. But there is no progress with this issue. He is using his regular medicines for Diabetics and BP which he is using from earlier along with medicines suggested by neurologist, both Sugar and BP levels are also normal. Please anyone's let me know how to treat this problem.