Can you add late payments acquired after Chapter 13 is confirmed?

My friend filed bankruptcy in October and was paying her mortgage payments on time. Her husband did not file with her. In January her husband left her so her mortgage payments fell behind due to having only 1 income and still 4 children to take care of. They reconnected in May and are trying to catch up on the late mortgage payments which is really hard. Trustee payments are garnished so they are up to date. Right now she owes March-June. There has been no action from the mortgage company yet but she is trying to find out what options she has before this happens. Can the Chapter 13 be amended to include the past due payments she currently has?