Question:
Is an avel allowed to go during his shiva to be menachem avel someone else sitting shiva?
Answer:
This question, may an avel go to another avel to be menachem him, is discussed in Y”D 393-2 the opinion of the Shulchan Aruch and the minhag of the Sefardim is that it is permitted after the third day of shiva. However the opinion of the Rama and the Ashkenazi minhag is not to.
Sources:
Also see Aruch Hashulchan Y”D 393-8.