MIL wants to sell us house for great deal without realtor

We have been renting my MILs house for years, she has no intention of moving back into the house (unless shes moving in with us which we wont do). So we've been back and forth on asking if we can buy the house from her and shes been pretty wishy washy. She says she wants to look at taxes first and then doesnt get back to us or tell us interest is too high for us to buy. Or we ask her how much she wants for it so we can plan and save up and she never gets back to us.

She has finally come up with an offer. She owes 98k on the house so she wants to sell it to us for 98k AND give us a 40k down-payment so we'll only need a loan for 58k.

This is a great deal! It would be hard for us to purchase or rent a place on our own with the current market, so I told her we will take her offer and we are aiming for May. But I feel like there is a catch. She doesnt want to use a realtor. What should we be aware of?

A few bits of information: according to Zillow the house was purchase in 2012 by MIL for 142,500, she has a variable rate and an unassumable mortage. The house was built in 1959 and is worth about 300k in today's market.
There is no formal rent agreement. She occasionally does big stuff such as a redoing the heating or getting a new dishwasher (neither of which we asked for) but hasn't fixed the backdoor or gotten the warer damage on the bathroom floor assessed and fixed. Trying to get her to do the things we request is like pulling teeth and its a lot of back and forth between the company only being able to speak to the owner.

We have a toddler and would really love to settle into this house and be able to fix things as we see fit as well as have the equity. But I dont want to land us in how water either.