azathioprine used to treat asthma in children/DLA

hi,im new to the site and wonder if anyone can help me please.My son is 7 and has suffered from asthma since he was 6mths.His condition is discribed as chronic and he takes lots of medication .He was on steriods daily for nearly 2yrs and these were stopped in january and he now takes azathioprine(an immo suppresent) I am unable to find out any info rearding this drug and its use in children of frankies age.Can anyone help?

We have been advised by medical staff to claim the mobility component of DLA we have been refused and are appealing the decision has anyone got any info on mobility and asthma?or have any other parents been in this position,i dont want o claim something frankie isnt entitled too and take monies away frm someone who needs it.CAN ANYONE HELP??????????????? many thanks everyone xxx