Won't stay in bed...ever!

We think my son, who will be 3 in January, has SPD. Our evaluation is in 3 weeks.

My son has never been able to fall asleep on his own. As a child, he did not sleep through the night until 11 months. He had reflux issues and he screamed for the first 6 months whenever you put him down for anything. The screaming was non stop so we had to sleep sitting up in chairs in 4 hour shifts, my husband and I. Furthermore, he never stays in bed now. He was an early climber, so we needed to switch him to a toddler bed around 15-18 months. Since that time, every night has been torture.

Before we knew about SPD, we tried locking him in his room (Ferberizing him). That worked for maybe two weeks until he ripped off the door knob safety lock and nearly ripped the door off its hinges. We tried baby gates but all he does is scale them. Bedtime is usually a 2 hour process every night of him screaming, crying, etc. He eventually gives up and goes to bed but some time during the night he comes into our bed (we do not want him hurting himself climbing over gates at night so we take them down when he falls asleep). We used to put him back but he comes back in every hour, so I hate to say we just gave up.

The most frustrating part is I cannot tell now if he is manipulating us or if it is part of the disorder. He has other issues which make me think he could also have HFA such as toe walking and repeating words, etc.

I just do not know what to do. I do not want to be cruel but he needs his sleep (and so do I)! I would not mind the waking so much if he did went to bed on his own or without so much assistance because we have two other children and the entire house is disrupted until 10pm nearly ever night regardless of when we put him to bed.

Does anyone have a similar issue or any suggestions?