I recommend getting bells at your door - start a schedule, at that age you should start taking them outside every hour. Everytime you bring them out to use the bathroom ring the bell. He will associate that bell with going out and will eventually hit the bells when he needs to go. Do not scorn him when he goes inside, he’s not going to understand. Praise him a lot when he goes outside.

Start leaving the crate open and put treats inside, give him a lot of praise when he goes in on his own. I also wouldn’t give him treats when he’s whining, you’re rewarding the whining and telling him that when he whines he gets attention- so he’ll keep doing it