Few things important to note:
1. Father can gift his major son ( who is not a minor) any amt of money, property etc. Nothing would be taxable in the hands of the recipient as the giver / donor is a relative and gift recd from relative are not taxable.
2. Gift of a substantially high amount should always be documented. That is prepare a gift deed to avoid any future problems from income tax.
3. The said funds gifted should be out of the taxed funds of the relative. I.e the said funds were/ are brought to tax. I.e to say that the nature of funds transferred should be bonafide and free from any encumbrances.
4. The gifted money can be in any mode, cash or cheque. If father gifts money in cash/ cheque then the said money should be available with him.I. e already shown in his father's itr in current / previous years
5. The donee/ receiver are not required to show it in the itr notified. It is only when the case is selected for scrutiny / regular assessment at that time the receiver should be able to prove the ito.
6. No tax will arise in the hands of receiver as the person who is gifting is a relative.
7. It is always advisable to gift the money in an account payee cheque rather than depositing cash. It can be any bank, need not necessarily be a nationalized bank.