These ideas may not be practical but I will put them out there anyway. If his child and having a relationship with him is really that important to him:
Can / Will your brother move 2.5hrs away?
If not possible due to work. Is work flexible enough that he can work from home one week and be in the office the other. If this is possible then he can have week on week off 50/50 custody. It will mean he would need permanent accommodation in the area his ex is moving to and lives up there for his week's custody. (I know that sounds like a lot of hassle - but it is an option - and may be cheaper than the lawyers).
The ex may not be expecting a reply of - ok you can move with my son but I will move there too and have 50/50 custody. If her or her new partners ideas is to put distance in your brothers relationship then it fails. They may decide not to move.
Can / Will your brother move 2.5hrs away?
If not possible due to work. Is work flexible enough that he can work from home one week and be in the office the other. If this is possible then he can have week on week off 50/50 custody. It will mean he would need permanent accommodation in the area his ex is moving to and lives up there for his week's custody. (I know that sounds like a lot of hassle - but it is an option - and may be cheaper than the lawyers).
The ex may not be expecting a reply of - ok you can move with my son but I will move there too and have 50/50 custody. If her or her new partners ideas is to put distance in your brothers relationship then it fails. They may decide not to move.