Child's Legs Are Bowed, Prescribed Ossopan. Will He Outgrow This?

Question: Hi, My son is 15 month old and started walking at the age of 13 months.He is walking normally but his legs are bent slightly not like bowed legs but slightly. His foot is normal. When we checked with out pediatrician she said to do development assessment the physio who checks the baby does the right thing in right age. She checked and said there is not much gap between his knees, but only his tibial bone is bowed slightly which may due to Vitamin D deficiency and asked us to give Just XXXXXXX and Ossopan (Oral Suspensions) drops for 3 months and come later for assessment. During these 3 months, bowing has straightened out to an extent but not completely. Whoever see my boy they say his legs are bowed. Will he outgrow this in the coming months. If not what needs to be done for this? I am very much worried about it. There is no history of bowed legs in our family. He used to W-sit during initial months i.e when he started out crawling but once we came to know thats it is a bad way of sitting we change him immediately.
Other than this he is a very active baby. He walks...runs all the time and does not drip often.
Please let me know.

Thanks doctor. Currently he is taking 1 ml of Just XXXXXXX and 5 ml of Ossopan.I am positive about his condition but I would like to know what would be the treatment if it does not improve.