Agree. We did the same till found out that our daughter had been verbally abused by her classmates on their chat. The situation was awful and our daughter didn't tell us anything because she is a very shy girl. We also could do nothing with her classmates. So we decided to install the mspy app and record all those conversations. It was very helpful in that situation.
I want to help my brother to make some new friends in real life or to find a new hobby.
You see, the problem is that spending a lot of time in front of the screen means that child in not interested in his or her life and try to escape.
My parents are too comformists to establish trust relationship with him. So, it's my responsibility.
I use them, parental control software is very helpful in this case. They're useful for limiting general screen time in case of very small and older children who can hear my explanation about the affections of gadgets on their health but anyway often ignore them.
Such programs and apps are very helpful for protecting children from various inapropriate content too and some of them are effective for teenagers too. There are many of them like Norton Online Family, Qustodio, Family Shield, Refog Keylogger https://www.refog.com/, Social Shield, Net Nanny etc. and all of them are very helpful for parents in case of monitoring their children gadgets activities and blocking resources with porn, drugs and so on. Such programs usually work in hidden mode too and are really hard to circumvent even for children with good technical skills.