sleep disturb early morning

i m trying to help my friend. He wakes up every day at 4 am, unable to go to sleep after that, sleeps around 10 pm every day. around 4 am he feels weak in legs and brain feels tired that time. if he gets up completely that feeling goes away, but if try to sleep same feeling starts. Right now i told him to try Joe's way of Arnica 30-c.
First, he took Arnica straight from Q bottle and two hours later he took Mag Phos 6x ( which I told him to take Mag Phos & Kali Phos at bedtime ). He said, after taking Mag Phos and Arnica 30-c two drops he was sleepy all morning.
There is a little improvement in falling a sleep after taking Arnica, Kali Phos, Mag Phos, but problem of waking up at 4 am not going away. His family Dr suggested eating late night snacks. Which did not help him. No history of BP, Diabetes.
But, person is heavy wt.
He took Kali Phos for few days when he woke up at 4 am. He said. it helped him falling a sleep within few minutes, but after that Kali Phos is not helping that much too. May be he is taking Kali Phos 6x, which is low potency. Another problem he said is his brain signals him that its getting close to 4 am and u will have this feeling start soon. Sometimes he checks the clock twice if its 4 am or not.
Any suggestions ?