Widowed Father Discerns Religious Vocation

My mother passed away a year ago and my father is now thinking about entering into a religious vocation - priest, brother, deacon, etc. He is retired Army, has a few medical problems, and has 5 grown-ish children. We are all very supportive of this decision because he had been in seminary before joining the Army. However he wants us to be weigh all the pros and cons and think deeply on how this will affect us and our families. Not knowing much about religious orders I'm not really sure what all the pros and cons are. Any information about this to help us make an informed decision would be very helpful.

God Bless!