There is a lot out there. My first suggestion is that if she hasn't already, she should find a support group or co-op in her area. This will be a life source and life saver for her more than anything.
These groups are where she will find friends for her son, friends (other homeschooling parents) for herself, opportunities for field trips, group discounts for curriculum, access to curriculum fairs in the area, and access to special needs resources for those who homeschool.
A place where she can find support groups and co-ops in her area is www.hslda.org. HSLDA is a legal advocacy group for homeschoolers, and you don't need to be a member to benefit from them. The site has information on how to get started, finding support groups in your area, your legal rights and requirements in each state, access to some of the more popular curriculum out there, and a calendar that lists when and where various homeschool curriculum fairs will be around the country and in her area. There is also a section specifically for parents of special needs children, which list resources and more.
They also have representatives available on line and by phone if she should need assistance with filing paperwork with her school district and more. She can also sign up (it's free) to be on their weekly mailing list where she'd recieve important information and updates concerning homeschooling both nationally and regionally.
Go to www.hslda.org and start by clicking on the "about homeschooling" button and take it from there. The site is packed with tons of information, but starting by clicking on that button will get her on the right track.
There are also a lot of parents like her who have chosen to homeschool children with special needs and they have blogs, produced curriculum and teaching guides based on their own experience and more.
Two sites I highly recommend are the following:
www.sizzlebop.com
http://www.headsupnow.com/about/
These two moms have written many fantastic books on teaching methods for special needs kids. They have links to products, curriculum, and other helpful resources. Your friend can also sign up to be on their mailing lists to get weekly newsletters, updates, and information on new products etc. One of the moms, Carol Barnier is a frequent favorite at homeschool curriculum fairs nationwide, and many of her presentations can be found on www.youtube.com.
She's very inspirational to anyone homeschooling a special needs child and her methods are practical not only for those with special needs kids, but any homeschooling parent looking to be more efficient and creative when teaching their child.
Here's one of her clips:
http://www.youtube.com/watch?v=geI_S6oe9sU
Here's a link to some of her best selling books:
http://www.westfieldacademy.org/zen-cart/