Thank you for your concern. "Suffering" may not be the proper or most respectful term because it makes assumptions about a "pitiable" way of being that may well be untrue. You surely would not want to portray a student's autism as "sufferable" when engaging his family.
As an educator, you may well feel a professional obligation to do all you can to ensure that a student is given every opportunity for treatment. However, pursuing an autism diagnosis is ultimately a parental decision, and is not something that can be imposed or forced.
If the subject has not yet been broached, you may be unaware of whether the family is already knowledgeable of their child's way of being. They may be exploring it in their own way and in their own time. We may see the urgency in early detection, but many families are in denial or may be scared to consider autism as an option. If you are not gentle and sensitive to the family's needs by meeting them where they're at, you could risk offending or humiliating them.
Ask yourself: How knowledgeable am I about potential autism traits and signs? Have I consulted with the child's school team or school psychologist or evaluator? Could the child experience, instead, dyslexia, reactive attachment disorder, post-traumatic stress disorder, or some other issue that may not be autism but still cause for concern?
My article, "Everyone has Autism," found at www.williamstillman.com, may be one resource to break the ice as an entree into a family discussion about your questions or concerns.