Help

  1. He will be of great help to you.
    1a. He will be of great help for you.
  2. It is a great help to you.
  3. It is a great help for you.
    Are these sentences OK?
  1. He will be of great help to you. – OK.
    1a. He will be of great help for you. – Not impossible I suppose, but doesn’t seem very natural.
  2. It is a great help to you. – OK.
  3. It is a great help for you. – OK, but “to” is probably more usual.