My boyfriend stopped holding his snake for a while she is aggressive now is there a way to tame her

There are two things that could be happening-

1. the snake is hungry and will strike at what is close or

2. the snake is not being handled regularly and becoming used to anything going into the cage being food and striking at the first thing that is presented to it. Like your boyfriend's hand.

I have had and rehabilitated snakes into regular human contact.

If the snake strikes when your boyfriend puts his hand into the cage the best thing is for him to wrap his hand into a towel and pick up the snake around mid-lentgh. The snake might still strike but hopefully it will strike where the towel is. After the snake gets past the first strike and realizes that what is in front of him isn't food, it will calm down and settle down.

Once he settles down the snake he needs to handle it regularly. The other thing is to not feed his snake in the same cage in which it lives. For all my snakes I have fed it in a regular place that is not the cage in which it lives. I always use the same box so that it smells the same to the snake. When you put the snake into it's feeding box, it knows that it is about to be fed. This keeps it from acquainting it's regular cage with it's feeding box so that when your boyfriend wants to take the snake out and handle it, the snake doesn't confuse your boyfriend's hand with the expectation of being fed.

The main point is that your boyfriend needs to handle the snake regularly, if not he needs to get rid of the snake. If he doesn't care for the snake enough to take the time to handle the snake daily, he should get rid of it. There is a responsibilty as an owner to take the time and care for pets whether it is a dog or a cat or a snake. It may be cool to own a snake but it is not cool to mistreat an animal.