Difficult LSCS patient

Hello! Could you kindly give me some advices?
1. 64 years old male. His job is taxi driver and farmer.
2. History
30 years ago he was operated on for lumber herniated disc of L4/5(Love method?).
One year after the operation he had low back pain and recommended to have an operation again but he didn’t.
6 years ago he was operated on for cervical myelopathy.
5 years ago he was operated on for artificial cardiac valve.
At July of 2010 he had back pain and healed with medicine. But in winter he had left buttock pain and left leg P&N and referred to me.
3. Symptom
Whenever he walks he has left buttock pain and radial pain on lateral side of left lower extremity and has P&N on lateral side of the left leg and below. But when he walks backwards pain and P&N is alleviated a little.
When he goes to bed he cannot sleep in spine position and so he sleeps in half side-lying on right side with support cushion behind his back.
4. MRI
Disc degeneration L1/2~L4/5
LSCS (R)L4/5 (L)L4/5 L5/S
5. Aggravation
Standing with back straight, Walking and sitting for a long time
6. Alleviation
Lumber flexion and right side flexion
7. Irritability
It took five minutes for alleviation at first interview but now it alleviates instantly when the physio takes the hip into full flexion, medial rotation and adduction in supine position.
8. Observation
In standing he shows list for right side. It may be a posture for escaping from pain.
9. Active movement
In flexion he can touch the floor.
In extension he has a buttock and radial pain.
In right side flexion it alleviates his buttock pain.
In left side flexion it aggravates his pain.
In rotation for both sides it aggravates his pain.
Combined movement for relieving pain is flexion, right side flex and right side rotation.
10. Neurological test
(1) Power (R) (L)
EHL 5 3
Peroneus 5 4
(2)ankle jerk - -
11. He cannot take prone position and so I cannot perform PAIVMs exanimation.
12. ROM of left hip medial rotation is remarkably limited.
13. Interpretation
Lumber segment hypomobility
14. Treatment
(1)Rotation mobilization in side-lying on the right
It aggravates his P&N in left leg.
(2) Specific distraction for L5/S in lumber flexion -> not effective
(3) Lumber traction by pull of only left leg -> effective for pain and P&N
(4) ROM exercise of left hip medial rotation -> effective for pain and P&N
After this exercise ROM is improved but at the beginning of every next treatment I can find limitation of ROM again.
(5) Lumber stretching in long sitting -> effective
It is performed with both hip abduction simultaneously or with both legs closed when he flex the lumber.
15. Result of the treatment
I have treated him for six months. I can eliminate his left buttock pain and P&N in left leg in supine position with his hip flex and medial rotation but he still has pain and P&N in standing and walking. He still cannot go to bed in supine position.
Could anyone kindly tell me the pathophysiology of his symptom and what should I do to eliminate his pain?

Thanks in advance
Novice PT