What should be the maximum amount I can pay off with professional help?

Your friend can repay that amount if he has a steady income source. I believe there's no such limit on maximum amount.

It will depend on how well the debt settlement company negotiate with the creditors and how much you have saved in the trust account.

As far as I know, there is no limit on maximum amount but it has to be an achievable amount like an amount which is possible for a person to repay.

Yes, it will depend on your financial situation how much debt you can comfortably repay. However, $40,000 you can pay off with professional help if you have a steady income.

That's a big amount. Who is the creditor? Usually, settlement companies are able to reduce your debt amount by 50% - 60%. Some creditors also agree to slash debt amount by 40%.