Whether or not "don't spend your families life savings on your startup" is good advice or not really depends on the amount of the savings, the age of the individual/family, and the family's earning potential, etc.

Losing all of your $20k savings at age 25, DINK family: hurts, but not life-changing in any way (as long as your spouse is OK with it, and you'd better be damn sure they aren't lying to you when if they say it's OK)

Losing all of you $200k savings at age 35, two small children and stay-at-home spouse: extraordinarily painful and will impact every decision you make for a long time.