An unusually prolonged or complex illness, esp. one that causes severe organ dysfunction or threatens life. Catastrophic illnesses often make exceptional demands on patients, caregivers, families, and health care resources.
However, if your current mortgage lender has discounted your current mortgage loan balance, the mandatory waiting period after loan modification is 12 months from the effective date of the loan modification with a 12 months on time payment history which is reflected on your credit report.
As for 3 year wait, that specific period typically refers to using FHA loan to purchase after a short sale or foreclosure. Possibly if you were in default (notice of default) before your modification some purchase lenders might view that same as foreclosure and require 3 year wait.