• Property sale to immediate family

Hello,

My dad is getting a multi story house constructed. To support him in the costs of construction, me and my wife will pay him a certain amount and he will give us one floor of the completed house.

We would like to transfer the money to him as soon as possible as the construction has started and he needs funds but we dont want to create any tax or legal problems for him. I have the following questions-

1. Is doing sale deed between two immediate family members the only way to accomplish our goal or is there any better way like gift deed, loan, will etc

2. In case sale is only way, can we send him the funds already or do we neccessarily have to make sale agreement with him first? As we both live abroad and cannot go to India at the present moment for sale agreement signing, we would prefer to transfer the funds directly and then just get sale deed registered if possible. Is that ok from accounts and legal perspective? 

3. If we must do sale agreement beforehand, we have been advised to do digital signing as we cannot be there in person. Is this also permitted for property sale agreements? We don't have any digital signature certificate (my wife is OCI so no Aadhar card or PAN either for her). Is this a long process to get this?

4. How much of the sale funds can we transfer to my dad before signing sale agreement without us or him having any legal or tax problems? 

5. Any other solution possible as we need to send funds to my dad as soon as possible?

6. When my dad (retired) pays constructions costs to builder, is TDS deducted at 5% via 194M or at 2% via 194C?

Thanks and kind regards