It is not a requirement in the prayers on behalf of the deceased that they are not offered at the same time. They can offer the prayers based on their own circumstances and time.
Khums is not obligatory on expenses if they were spent in prohibited ways. However, a believer is expected not to perform any prohibited thing even if he thinks it is small, since it is a disobedience to Almighty Allah.
Intoxicating alcohol is najis and when it touches the body or the clothes, they should be purified before praying or the najis clothing must be removed.
