You can crate train him, but do it gradually. I'd feed him in there and leave the door open. Leave his water in there too, so that's the only place he eats and drinks. Have some toys in there and let him come and go for a few days without shutting the door on him. Then after he's had some exercise and he's tired, try putting him in there and shutting the door for a while. Don't open it for him if he cries, but wait till he is quiet. Always give a command and a treat when he goes in and never associate it with punishment.
Teach him to go potty outside only. Take him out often and praise when he goes outside. Don't punish for accidents because it's not his fault. You need to watch him literally every second that he's loose in the house. Preventing accidents is the best way to teach him. You don't need to wake him to take him outside but be ready the second he wakes up, after eating, drinking, playtime etc, every half hour to 45 minutes otherwise. There are other threads with good potty training info. Do a search.
Four hours is as long as a pup should stay in there at a time. Also, in general, excessive confinement is not good for a pup. They need your companionship, training, and stimulation which they can't get if they're in a crate all the time.
It is helpful to have the crate in your room with you at night.