As long as the 70 year old man stays active and hasn't smoked in their life or has quit smoking earlier in life then the 70 year old man could live to 90 to 95 or even 100 years old.
What causes death early on even at 70 is due to either diseases or inactivity or when they smoke cigarettes.
Some people just sit around in their lounge chair or rocking chair after retirement without staying active and doing at least something which causes health problems and makes it hard for the person to move due to joint problems.
Staying active and walking around, riding bicycles etc and staying busy doing some hobbies can help you extend your life.