Arogyam package test result shows imbalance in Homocystein level and vitamin B12 and D3 levels are very low?

Recently, my brother(26 Years) started felling multiple symptoms of fatigue, lack of interest and poor concentrations.
We consulted a Psychiatrist and on his advise we conducted all the test from Arogyam package. The test result shows imbalance in Homocystein level and vitamin B12 and D3 levels are very low.

I went to a physician in Lucknow and he said he does not recognize Arogyam report and ordered test from his own clinic. I requested him to treat the B12 and D3 deficiency immediately via injection or other methods but he’s adament for report from his own lab. This induces doubt about his intention.

To all the esteemed panel of doctors here, I have couple of questions.

1. Is it the Vitamin B12/D3deficiency or Homocystein imbalance thats causing the above mentioned symptoms of lack of interest and fatigue.
2. As my brother is working in a very pivotal position with a cosulting firm. So can any of you suggest a suitable treatment which is effective and and works in less time.
3. Can any of you also suggest suitable doctor nearby Lucknow/Hyderabad who can do the job easily and quickly.
Please help.