best cctv options

hi all new to the site so please point me in the direction if this is in the wrong place. i am installing a cctv system for a friend who's mother has alzheimers so she can keep an eye on her at home etc, the budget is around £200 4 cameras are needed ideally wireless, dont need to record just need to be able to check the cameras over an android app with ease as they arent very technical,audio is not required,and fairly easy to setup,attempted to install an annke today but it kept freezing and not working had a mind of its own so thats being sent back,any suggestions to system with these requirements would be very welcome, thanks in advance