Question about housebreaking a Chihuahua I rescued?

I adopted a 5 mth old male Chihuahua and for the 1st 5 mths of his life he spent it in a bathroom. He was allowed to eliminate anywhere he wanted. Now that I have him I am trying to crate train him. I understand he is a baby and can hold his bladder for 5 hrs at the most. He is under 4 lbs and I keep him in a cat kennel so it is pretty small. I let him out at 6am, 12, 3, 6, 8, 10pm. And then he usually wakes me up between 1 and 4am to go out again. But he is still having accidents in his kennel. I was using blankets in there but that would just absorb the pee or if he pooped then he would shove it under the blanket. I tried to put nothing in there and if he peed he was covered in it. I know that he was not trained from birth but it just seems like he is not getting the hang of it. I have an older female Chihuahua (almost2) in the house too and she is house broken. I thought that maybe he could learn from her. I also thought that they would not go where they sleep? Help!!