Gave mom $1000 per month
Gave Dad a car 3 years ago ( car was relatively cheap then)
At least he got a car to drive for the next 7 years.

Dad is still working
mom is taking care of the kids.
Both parents no outstanding loan, just worry about utlities and car expenses.

Also, birthday presents, CNY 'bonus' and occasional holidays
Spending on parents, $20K to $30K per year ave.
Returns : priceless