dear Client,
1.lodge police complaint in PS of ur area against your jija for illegally living in his father-in-law house and for trying to beat you asap.
2.file suit for possession for said house and damages in civil court against ur jija asap.
3.you can claim damages in said suit for possession because ur jija is not paying any rent to you for last many years.
4.take all above stated legal actions against ur jija with the help of local lawyer.