I have great sympathy for your personal circumstances, but for the purposes of an appeal I would suggest the focus needs to be as much as possible on why this would be the right school for your child.
I assume we're talking here about a partially selective school. The best approach is probably to put forward as broad a case as possible as to why this particular school would best meet your child's social and academic needs.
I'm afraid the success rate for some of the foundation schools in your area is not high. No reason not to try, however.
The sort of evidence you might consider is covered in the Q&As, e.g. http://www.elevenplusexams.co.uk/11plus ... rs.php#b11
http://www.elevenplusexams.co.uk/11plus ... ers.php#c2
(see no. 17)