Tony,
The biggest mistake they made (and it defeats anything and everything else they did) was to *not* replace that beam/girder and try to add new wood to the sides of it.
If nailed or lag bolted to the old beam/girder, what are the nails going into? Decayed/termite damaged wood?
If they tried to through bolt from new wood to new wood, the old would in the center defeats much or most of the strength they were trying to add with the new wood. Those two new wood peices need substantial and stable support between them, and that old decayed/termite damaged wood will not provide that.
Hopefully, Brandon Chew will comment further (and, hopefully, not shoot my thinking full of holes
).