No, it doesn't matter if he is travelling daily or weekly or once in two weeks but the thing is he should be a Canadian resident to get the exemption from quarantine. If his residence is still in US and wants to commute, he might not be put in essential travellers list.
As far i understood, you will be shifting your residence to Canada permanently and then he will start his commute, is that it? or only you are moving? If only you are moving but if your husband isn't moving, he will not be exempted from quarantine. ( Best bet in this case would be, he moving off completely to Canada with you. i mean permanent move, but commute daily/weekly to his US apartment to work, and at border(US POE) , when asked tell officer that he is travelling to work, and about work location and stuff he would say actual work location(i mean the company where he works, hope its in Detroit?) but travel to his apartment and work. no worries, while returning at Canadian POE, same thing)
2. This can be answered by
@harirajmohan/
@canprofus .
3. No issues at US poe. many people have been commuting daily.