You have two field with the same name (HIPPO) - you might want to one of them.
select clientid
,ClientSort as ClientName
,'Y' as Enabled
,'N' as HIPPA
,matternum
,case
when charindex(@s,[description])>0
then left(cast([description] as varchar(max)),charindex(@s,[description])-1)
else [description]
end as MatterName
,'Y' as Enable
,'N' as HIPPA
,areaoflaw
from matters
order by Clientid
,matterid
;