If you want to aim for Brent area, I would suggest changing entry points, and doing a tow from Crane Lake to Bottle P or to McAree (if Bottle is taken). This will reduce the portaging. He could use paddles as 'walking sticks'. You will also want to consider that getting to/from  Brent will involve some up & down and some serious mudholes. It is possible he will need assistance at some points.

I agree that he should test any system pre-trip to learn what adjustments may need to be made. He should also consider that his pain will significantly increase and how he plans to treat it.