I was thinking of a sweat equity type of situation but I don't know how he would go about getting that arranged or if D's mother refuses it how he could legally stake a claim to the property since he will be paying 50% of the mortgage payments and at least half the babysitting responsibilities.

I'd suggest you take a RE class, business law and a finance course, none will hurt you.Come out thinking how to work smarter not harder, I have always hated to sweat unless it was from recreational activities.Learn to recognize deals by the property not by a system.

In this area, I knew my sweat equity wouldn’t go too far but felt good about the monthly rental income.

I can provide the cash to purchase and was thinking the partner would foot the rehab and sweat equity.

Most of our deals require a decent amount of sweat equity to get a decent return.

House hack, but only if/when you can find a great deal where you can add some sweat equity.

Im asking myself this same question but with different  circumstances.I have 6 properties all cash flowing nicely.I have a  renter who wants a bigger place.So ive decided to buy a 2 family that's more then I've ever payed for an investment.There's no sweat equity and I don't expect it to go up in value over the next few years.I'll only be making 6% on my 60k down payment.  

(I want to get it to where I can wing myself off of using their money)A strategy I want to implement is to buy a cheap property, put in some sweat equity and get a mortgage on it down the road to essentially get all of my funds back out of the deal and then some  to fund my next deal. 

It sounds like you put a lot of blood, sweat and tears in it and it paid off. 

Really to get started you do need some money, but sweat equity is another great way to get ahead as you have found out.