Divorce

My friend is international student in Australia. She wass married in March 2016 and both came Australia together in July 2018. Things went smooth earlier, but now she is going through rough phase of her married life. They are living seperately from more than 12 months from now (which makes them eligible for application of divorce). She is unsure, that her better half will aggree for divorce (ego problem). Though she is going to file her divorce next month, just wondering, if her husband doesn't respond to the summons, what could be the consequences? She will be able to get one sided divorce. Will that be valid in India? Can he challenge the decision in India despite of recieving summons here? Can his family do something to stop the divorce to happen? Also, after getting divorce, which incase is not mutual, after how long she can marry legally? Note: She is primary applicant in her visa, after things were not going smooth, she informed immigration of their separation which resulted in his visa cancellation. He is living on some other visa now.