I have a sub panel out to a mother in law. There is lug power at the panel but there is no power at the circuit breakers. Changed all outlets, switches and GFCI, checked for loose splices.

"lug power" at the panel means which panel? The subpanel at the mother in law unit or the source panel?
Does the subpanel (mother in law end=MIL) have the supply wires landed on the lugs of a circuit breaker or directly on lugs bolted to the bus bars?
Check the supply side, say if it comes from a circuit breaker and that you have checked power coming out of that end or not, then check the other (MIL) end again.
If it is on a circuit breaker at MIL end, try resetting that circuit breaker by turning it all the way off first and the back to the on position.

please post what you find