My bt's ears were floppy for a while. I thought they weren't going to stand up but they did. I'm sure your little ones will stand too. Your pups are cute
If your BT puppy's ears are going to stand, they will be up by the time they are around 6 months old. They should show signs of strengthening and going up off and on from about 3 months onward. Teething keeps a lot of puppy's ears up and down, forward and backward curling, etc.
Were his parents and grand parents ears erect? Does he have heavy ear leather? Some Boston ears never go up, depends on their genes.
It is so cute to see their ears start to stand! I left to go to work one morning and buddys ears were still flopped over, and when I came home from work, they were standing up and stayed up. All dogs are different I think with how they do it, but JeanEsBostons is deffinatly right, not all of them stand up. But you will be able to notice a change.