If he feels good and refreshing both times when he wakes up then is it good Usually a good sleep time is 6-8 hrs in a 24 HR cycle

Hello.......see there are two modes of sleep Non REM and REM sleep.. There are four stages in non REM sleep ,These stages progress cyclically from stage 1  through REM then begin again with stage 1. You feel refreshed with deep sleep..Stage 3 and 4 are deep sleep  stage .. It takes time to reach that  stage. If you only  have superficial sleep and wake up, you will be tired whole day..  Adjust  timings according to your convenience