~also the average unspend output is 148 bytes when used as an input.
~
only if he was mining after 2012 (release of bitcoin core v 0.6) and also was mining to an address with compressed private key. otherwise it is going to be ~179 bytes.
=59,070 sat per unspent
adding 150-180 s/b can get a confirmation within reasonable time or it can take weeks. you can also try ViaBtc accelerator with much less fee (10+ s/b) but it is crowded these days and it is tough to submit a tx there.
https://www.viabtc.com/tools/txaccelerator/remember to mark your transaction to be replaceable by fee (RBF) so you can bump the fee if it was unsuccessful.