If you want to buy the best mobile for your sister, brother. I will recommend to you you must buy the Realme 6i mobile, now I talk about this mobile future to another brand mobile, it best mobile
Full HD display 6.5 inch, if talk about the camera to amazing 48MP+8MP+2MP+2MP Front Camera 16MP and also make a sol motion video in HD, the battery is so powerful 4300 mAh, if you interest to play a game like that PUBG GAME this mobile processor good "Media Tek Helio G90T" this mobile weight 191g
RAM 4GB, AND ROM 64GB Expandable up to 256GB