will allah forgive?

In my Teen age I used to watch nude pictures when I browse.even I know its haraam I can´t control myself bcz of my weak Imaan.Also I watched infront of my cousin brother (who is less than my age) (who is really shy to watch) bcz sometimes he comes with me.So he also got used to this habit.But After crossing my teenage I came to learn it’s a big sin so I sincerely repented to ALLAH and I completelety gave up tat sin.So I also advised my cousin(THRU EMAIL) its haraam and to get sincere repentance to ALLAH.He told me ok.But still I came to know he is addicted in watching nude pictures..so I would like to know tat 1) allah will accept my repentence since I left tat sin?? 2)or allah will punish me since I taught tat big sin to my cousin who is still practicing ? 3)and also I want know tat the particular sin committed by my cousin will be added as my sin in my book tat will be given to me in Judgement day or since I taught tat sin to my cousin who is innocent? So I want to know how to get rid of tat sin and ask repentence to allah so tat allah will

Dear Brother / Sister,

There is no sin which may not be forgiven provided that you repent for it. The repentances which satisfy the conditions are always accepted. You must repent sincerely with the determination of not committing the same sin again.

Please read the articles given below by clicking on them;

Can you give information about Allah’s mercy for the sinners?

What is the meaning of “Having a good opinion about Allah and being between hope and fear”?

What is the sincere repentance (tawbah nasuh)?

Forgiveness in the Month of Ramadan

Questions on Islam