With some limited exception for truck drivers, pilots etc, you employer can work you until your drop and then start all over again--just so long as they keep paying you (OT I presume) They need not accomodate your personal/family needs and they can fire you if you don't work as directed.. For cause!
Due to some issues of excessive hours for medical residents there may be caps for some medical professionals _I do NOT know if they apply to RN's
If you employer is large enough and you have been on staff for at least 1 year you probably have some rights to seek up to XX? days off per year (unpaid) under FMLA for medical needs within imediate family but not babysitting and I'd not venture a bet on what the status of care for an autistic child is. .
Its usually not cost effective to pile on constant OT when one can hire folks straight time for ongoing situations...whats going on?
Many folks work 60-70 hours a week ---and I have some younger friends who routinely put in 100+
No work could worse than too much work?