Family visa for graduation

Hello

I am new here so please bare with me, I permanently live in the UK and have just finished my degree.

I want to apply for my mum (40), and son (6) to come for my graduation, at least 10 days. They both live in Zimbabwe. My mom does not work due to taking care of my son therefore I send her money every month. And my son is in school now.

I am planning to book a hotel for some days but she will as well come to my house later.
My worry is, I only have a water bill and TV licence and obviously letter in my name.

Can you please advise me before I apply.
I really appreciate your help.

What evidence of strong ties to home country (social, employment, income, property, savings, etc etc) will she submit to convince an ECO that she is a genuine visitor and will leave the UK??

If you support her financially, this will weaken her application.