Good to hear that your wife's OK.. after all this work, at least she might still want to ride the bike
The good news is that it doesn't look like anything too weird...
Looks like it was built for 26x1"/650C/571mm
Going by the axle to brake length:
571mm/2 = 285.5mm. Nicely in the middle of the brake adjustment.
Going by the bridge clearance:
571+ (2x23mm tyre, typically) = 617mm total diameter, divide by 2 to give radius = 308mm giving 12mm of tyre clearance under the bridge.
You do still have the option of going for the slightly smaller MTB 26" wheels at 559mm. This would let you fit tyres up to around 28-30mm fat, but you would need to source some deeper drop 49-59mm drop brakes to make up for the 12mm smaller diameter rims.
All the best,
Pause, take a breath and ask yourself: "What would Rastamouse