Active Time Details

My husbands active time details has been changing the last couple of days I have noticed, possibly longer than that and I wasn’t paying attention. The total time connected goes down from one hour to the next and apps it shows that he used the last hour no longer show that they were used. All of this occurs in the same day. How is this possible? I do not know if this is an xfinity issue or if my husband is doing something to manipulate his usage in order to hide what he is doing. Also, his iPhone and iPad randomly show that they are asleep when my iPhone and iPad  are right next to his and supposedly have not been used all night and mine show strong connection to wifi and his shows his iPad is asleep and his iPhone shows weak signal. Please help!! This makes no sense to me unless my husband is doing something in order to hide what he is doing?