Capital gain provision utilization

"if I buy a plot on my name (we are siblings), can he construct the house using the capital gain money deposited in the account in his name."

Are you planing on having this property under joint name? If the money is actually utilized for the required purpose then it is sufficient. There have been a few cases wherein it was held that its not necessary that property should be held in own name

"Or He make the payment for land in which is certainly much more than the capital gain provision deposited in bank, and balance amount I pay in this way can he buy the land or property on joint name using the capital gain funds."

As long as he is going to has share in the house property commensurate with his cap gain, its valid

"What if he just buy the land with capital gain funds and not construct a house still he is elegible for examption of capital gain tax (2013-2014 financial year.)"

That would disentitle him from exemption. Exemption is allowed for amount utilized towards procuring the land because it is necessary for the purpose of constructing the house property. But if the intent is not to construct then you would also not be entitled to claim any exemption

[Not citing cases unless asked for]