Germany Infos Needed !

Nairalanders, A friend of mine ask me to help me out with this questions, He applied for a Germany short term visa sometimes April to attend a conference and he got a 4 days visa that he wrote in the application form but he didnt travel to Germany.Now,he wants to apply again to travel to Germany to attend a 3 days conference which he will definitely go.He wants to know if he can write there on the application form that he needs 3months which is 90 days visa because they gave him 4 days visa the first time, Can he write on the form that he needs 90 days visa.Is it possible. Hope to read back from you all, One love

i checked the site but couldnt really understand what they mean with the stuff