First of all, if you lent money to your relative as stated by you. Then, is that transaction evidenced in writing? If you have any written acknowledgement of money lent by you, then you can file a Summary Civil Suit.
Since, you gave Rs. 4 Lakhs in Cash and if you don't have any written or documentary proof related to the transaction. In that event, you cannot file Summary Civil Suit for recover of money amounting to Rs. 4 Lacs!
For recovering this Rs. 4 Lacs in cash you need to file Ordinary/Regular Civil Suit at District Civil Court. The burden of proving the case will rest on you. Regular/Ordinary Civil Suit can take 3-4 years to be decided by the Court, subject to pendency of cases in the District Civil Court.
Summary Civil Suit is an effective and speedy remedy for recovering money. It is filed under Order XXXVII (Order 37) of the Code of Civil Procedure. You also need to pay court-fees on the amount claimed by you in the suit. Court-fees is generally 4% to 5% of the amount claimed in the Suit.
Also, remember that there is time-limit for file civil suit for recovery of money. This limitation period to file a civil suit is mostly 3 Years from the date of cause of action.
First, send a legal notice through an advocate. Advocates generally charge 10% of the principal amount claimed in the suit towards their legal fees.
If you are in Andhra Pradesh, then you can claim additional expenses incurred by you for prosecuting this case under A.P. Advocate Fee Rules Act, 2010. In case of other states, the legal expenses can be claimed according to High Court Rules. Remember, this has to be stated in the plaint or else court may exercise its discretion whether to award you legal fees or not while decreeing the suit.
Summary Civil Suits under Order 37 of C.P.C. is generally disposed off within 12-14 months, if contested by the opposite party. If the suit is not contested by Opposite Party(Respondent/Debtor) then you may get an ex-parte decree within 8-9 months.
All this is subject to pendency of cases/lawsuits within the District Court where you intend to file the lawsuit.
Make a list of movable and immovable properties owned by Debtor as this information will be required by you for carrying out execution of your Decree. In case, you are unaware of the details of the movable or immovable properties owned by Debtor/Respondent/Opposite Party, then you can file an application under Order XXI Rule 41(2) of the C.P.C. for examination of Debtor(Opposite Party). The court will order/direct the Opposite Party to file affidavit stating their details of properties. If Opposite Party(Debtor) fails to file affidavit of his assets, then he can be detained in Civil Prison for upto 3 months, subject ot payment of Subsistence Allowance by you. Subsistence Allowance paid by you for detaining Debtor/Opposite Party can be claimed by you as cost of suit in addition to the Court-fees paid.
Remember, one thing even if you win the lawsuit, the opposite party(debtor) can appeal in the High Court for setting aside the decree/order given in your favour. Round 2 of your legal Battle will be at High Court. Whoever, loses Round 2 at High Court has an option to file appeal in the Supreme Court. Round 3 of your Legal Battle at Supreme Court. Whoever, loses Round 3 at Supreme Court will have an option to file review petition invoking Article 137 of the Constitution. This will be Round 4 of your legal battle. However, there is no guarantee that Supreme Court will entertain the review Petition under Article 137 of the Constitution. This discretion rests with Supreme Court.
After Round 4 is over and you emerge victorious, only then you can proceed to execute the Decree/Order in order to recover your money.
When you have won the Round 4 of your legal battle, then you can apply to the District Court where Debtor's property is situate for conducting sale of his movable/immovable property in order to realize the fruits of your Decree.
Conclusion of Round 4 of legal battle at Supreme Court might take 8-10 Years from the date you have filed the case in District court (i.e.) the Court of 1st Instance.