Any advice on the language or a letter I can use to reach out to the cosigner?

I understand I might be do a mix of some of the ones I listed but I'm willing to learn and be adaptable.

Accreditation is achieved by either proving the investor has a net worth of $1,000,000 not including primary residence; by proving that the investor has made $200,000 a year over the past 2 years, with a reasonable prediction to make that again this year; or by a letter of accreditation by a CPA, attorney, or other professional.

Which would be a matter of having your father write a brief letter, which should not impact your loan at all.

How do you handle this mix of emotion?

She just received a letter from them, 71 days after stating that they are not only keeping the deposit, but she owes them money.

I just received a letter from the city stating that the property has appraised for $177,00.

Mixing money and family is a recipe for disaster, particularly when that money is supposed to be for your retirement.

The letter should encourage the tenant to communicate so you can work something out.

The better comparison when evaluating what to invest a tax-sheltered retirement plan into is what else the plan could be investing in, and where you can find the best overall mix of security and income production.