All my bugs that I found on minecraft pe

1:my brother when he connects it does not say he connected and after 10
sec he disconnects randomly
2:every time I build something on my world when I come back its not there anymore
3:every time someone join and touch a chest there game crash
4:sometimes I get hurt when no one on my server and its on peaceful
5:everytime someone join and you build something on ice the floor for them is water
6:sometimes your game gets lag for no reason
Thx for reading this a plz fix those bugs!😡