If possible, please post the specifics. What is the provision and is it part of your son's IEP? How has this become a safety issue? Changes to an IEP cannot be made arbitrarily and there is a process for appealing decisions in which you disagree.
I'm sorry, your information about what the school plans to change is still incomplete (Maybe too sensitive to post?).
Regardless, any amendment to an IEP must be made with agreement by the school district and the parents. Periodically the school should send you a notice of Procedural Safeguards which are your rights and responsibilities under IDEA. This document should outline the appeals process when you have a disagreement with the school.
If you think consulting with your son's doctors will help, you should initiate the process. Additionally, you may want to consult with an Advocate at a Parent Training and Information Center (Federally funded centers in each state that provide advice and information for parents of children with disabilities.). Staff at these centers should be able to help you understand your rights and how to appeal the decision or make changes as necessary. To find a center nearest your home go to: http://www.parentcenternetwork.org/parentcenterlisting.html
I hope this is helpful. You may send me a message by clicking on my name above this post should you have additional questions.
You have a lot of rights, you need to consult a professional.