I've heard about it; whether it was true or not, I do not know. When I asked myself about it on this topic, my mind consistently denied this allegation. He was more than 70 years old when these allegations came up; is it even possible for an old guy to be sexually harassing someone or get into scandals at that age. At the same time, I would look at the good works that he did. I don't think it's simply possible to earn millions of devotees if he really led a scandalous life; at least, people close to him would have known it or leaked such info had it been true.
Bottom line is- I do not know, all I know is if there were at least 1-2 Sai Babas in Nepal, the face of the country would change for the better; if nothing, he's at least a devoted social worker; and anyone who spends their entire life serving a society is no less than divine.