He has not filed taxes in the last couple of years? That would be a concern for outstanding tax liabilities. Most factoring companies would question that. Even if they could get past that issue you have AR of 138k. Best would be 85% of that to start and increase as they get more AR and taxes filed.
No bank will go 10 years unsecured with no tax returns filed. Have him file his taxes and go to SBA.
Or try loanme. to start
If you need assistance on the AR LOC we can help.

Ben