SELECT * 
FROM
(
SELECT DISTINCT ON (t1.nus)
t1.aus,
t1.nus,
t1.sts,
t1.fki
FROM t1
WHERE t1.fki = 85
ORDER BY t1.nus, t1.aus DESC
) as s1
WHERE s1.sts = true;

--

SELECT * 
FROM
(
SELECT DISTINCT ON (t2.num)
t2.aum,
t2.num,
t2.stm,
t2.ptm
FROM t2
ORDER BY t2.num, t2.aum DESC
) as s2
WHERE s2.stm = true;

with ...

select .. .. .. as item from
(SELECT * FROM (SELECT DISTINCT ON (t1.nus)
t1.aus, t1.nus, t1.sts, t1.fki
FROM t1
WHERE t1.fki = 85
ORDER BY t1.nus, t1.aus DESC
) as s1
WHERE s1.sts = true
) n1
inner join
(SELECT * FROM (SELECT DISTINCT ON (t2.num)
t2.aum, t2.num, t2.stm, t2.ptm
FROM t2
ORDER BY t2.num, t2.aum DESC
) as s2
WHERE s2.stm = true
) n2
on (n2.ptm = n1.fki)
group by  n1.aus
order by n1.aus
)            

...