SQL Trigger based on a condition in another table with several rows (UPDATE)

Question

I am trying to create a trigger on one table that is conditional on what could be several rows in another table.

Table 1 = sysid, decision
Table 2 = sysid, user, status

Table 1  = 1, Pending
Table 2  = 1, Lisa, Approved
Table 2  = 1, Maggie, Approved
Table 2, = 1, Nancy, Pending

I Need Table 1 to change to Approved once Nancy has approved her record.

I need to update decision in table 1 if all the records have a status of approved in table 2

I am getting an update error. Can someone help please. I think it is the multiple records in table 2 that is causing the issue. If the trigger I'm posting is too confusing, just use the description. I am on 2012. Thank you.

CREATE TRIGGER [TR_] ON [Table 2] 
                AFTER   UPDATE
AS
if (UPDATE (T2.status))
     BEGIN
           SET NOCOUNT ON;

         update table 1
                Set T1.decision = 'Approved'
                    from
                (
                select DISTINCT sysid 
                from(

                     Select  T1.sysId  T2.status
                     ,LAG(T2.status) OVER(PARTITION BY T1.sysid Order by T1.sysid) as 
                     previousrecord
                     from table 1
                     left join table 2 on T2.sysid=T1.sysId 
                     Where decision <> 'Approved'
              )x
              where status = 'Approved' and previousrecord = 'Approved' OR (status = 
                'Approved' 
               and previousrecord IS 
                NULL)
                ) z
                where sysid = z.sysid

               END;