want a help/guidance

my son 45 is staying away from home at Dhanbad on the pretext that he is doing business there. Two persons under whom he is camping are only using him under the pretext of getting/ doing big business and they are using him to extract money from me. I am at 75 and my son creates great problem for me at times coming to house where I am alone. In fact he is doing no business there except following these two fellows. I am helpless. How can I get my son back from the clutch of these two?