Mail forwarding Massachusetts

My brother is retiring and splitting his time between MA and AZ.

they would like to start using a mail forwarding service, not for a domicile, just to simplify their mail. 
does anyone have a mail forwarding service in MA that they can recommend?

they don’t want to use USPS or UPS.

they have already been moving everything to online but there are still some things they get that they will need forwarded.

thanks

sue