Depends on what Bubba's "other issues" are but they could be the reason for a weak suck. She could try different size teats, there are some that you can buy that you can adjust the flow by holding the bottle in a certain position. I don't know the name sorry, someone on here might. There is a bottle called a
haberman feeder used with bubbas with special needs but I'm don't think you can buy this without a medical assessment. If it is a major issue she could ask her GP for a referral to a speech language therapist for assessment.