3 and 6.
The only exception would be if the SAHP is not really a SAHP but just sitting on their arse and refusing to work - if the children are at school and the working parent is doing all the housework, cooking, shopping, school runs and emotional work. Then the SAHP isn't a SAHP and not pulling their weight and the situation needs re thinking.
If the SAHP does 50 hours per week of working hours childcare for children under school age plus 50% of the childcare when both parents are home, that is "worth" whatever it would cost to pay for 50 hours per week of childcare.
If the SAHP does a disproportionate share of, or all the housework - cleaning, laundry, tidying, cooking, food shopping, shopping for children's clothing and necessities - than that is "worth" whatever it would cost to pay a housekeeper to do the imbalance.
If the SAHP is doing more than 50% of the family admin (filing, paying bills, running errands, dealing with trades people when the boiler breaks, booking holidays and whatever) the imbalance is also "worth" a PA rate for those hours.
Most of the time, having a SAHP "saves" a very substantial amount of money or of time outside work, as compared to what would be required if both parents were working identical hours. Therefore it has a financial value to the family unit.
People saying being a SAHP isn't work because being with your own children should be a pleasure otherwise you are a bad person presumably don't think any job you love is work, and presumably don't think SAHPs should be doing any more than the 50% of drudge work (cooking and cleaning and household admin, grocery shopping, laundry and tidying out cupboards etc. etc) that would be their fair share if both partners worked in full time paid roles.