autism.. or just plain naughty

I can't decide. Ben.....
Ben has taken to dropping his pants wherever he may be in the house and peeing on the carpet, etc. The house is his litter box. Now.. he knows he doesn't want to be wet, and he has to go. Is he being naughty.. or autism
It's a daily struggle I'm going thru on how to handle his behaviours and quirks. I really wonder if I'm giving him credit for knowing exactly what he's doing, and just being louzy at discipline.
I really do believe children do best with boundries and expectations. I SUCKED at that with my older two and they're currently paying the price. I constantly strived for peace. It was a tough situation with two CONSTANT teenage boys. If it wasn't one, it was the other, and how I made it through I don't know. They still haven't made it through. The older one is working two menial jobs and lives in FL. He sounds pretty happy, and he's just cruising through life. He turned 21 on Monday, and I have to remind him that at 21 cruising through life is acceptable, but he's only going to blink and be 30. Where does he want to be then?
The 18 yr old...... sigh.... I can't explain him. He's his own worst enemy. He has decided to take on a persona, and it's not a good one. He is actually a person that no one wants to be around. You can treat him with kindness, he'll see weakness. Have patience... he'll dig and dig and dig until he gets you. We had to ask him to leave.
He has gone to and been asked to leave:
both of his grandmothers houses
I sent him to FL where he wanted to be with his brother. I set him up with a roomate who works and goes to school. bascially never there. Told him I'd pay his first 3 months rent, and he just had to get a job. Within the first month, he did damage to the guys house, and was asked/told to leave.
He went to an establishment known as covenenant house. They take in teens, teach them life skills, and help them get an apartment/job/etc. He lasted 5 days. This is a place that is used to dealting with difficult kids.... 5 days.
He's now back in PA and I don't know where he goes from here. I know that everything he's doing he's pushing everyone further and further away. I know he needs something, but for the life of me.. I don't know what.
And then.. back to Ben. To know/suspect, that Ben will never have that "typical" life we all hope for our kids. It's a wonder I bother to get out of bed in the morning.
tired...tired...tired...
But, then he'll look at me, smile, close his eyes and give me a kiss..... ahhhhhhh