Dear DM, so sorry to hear this awful news. All grief is tough to cope with, and especially so when you've lost a young person, unexpectedly, in especially sad circumstances. You won't lose your mind, though it may feel that way at first. Explore the availability of grief counselling, perhaps through your local hospice, to help you deal with your grief ( which takes 6 to 9 months at least to lessen usefully ) and to enable you to be more helpful to her husband and child. Don't be afraid of crying.