He did tawaaf al-ifaadah when he was junub

There is grave major sin on this person
because he continued for all these days praying without being in a state of
purification. The Prophet (blessings and peace of Allah be upon him) said:
“Allah does not accept any prayer without purification.” What he must do
with regard to his prayers is repeat all the prayers that he did before
doing ghusl. 

With regard to Hajj, he has to repeat
tawaaf al-ifaadah, because he did tawaaf when he was in a state of janaabah,
and tawaaf is not acceptable from a person when he is in a state of janaabah.
That is because the one who is in a state of janaabah is not allowed to stay
in the mosque, as Allah, may He be exalted, says (interpretation of the
meaning): “O you who believe! Approach not As-Salat (the prayer) … nor
when you are in a state of Janaba, (i.e. in a state of sexual impurity and
have not yet taken a bath) except when travelling on the road (without
enough water, or just passing through a mosque)” [an-Nisa’ 4:43]. If he
was married, he should avoid intimacy with his wife until he goes back to
Makkah and does tawaaf al-ifaadah. In that case he should enter ihram for
‘umrah from the miqaat, then do tawaaf and sa‘i and cut his hair, then do
tawaaf al-ifaadah. In addition to all that, he must also repent to Allah by
regretting what he did and regarding himself as having fallen short and
neglected the rights of Allah, and he should resolve not to do such a thing
again. End quote.