help needed : Query about sponsoring my father's visit

[diyaabcd]

I am living in Uk for last three years and I wanted to sponsor my dad for visit to UK.
He lives with my mum who is a house wife and sister who is university studying for her degree.

I have all the relevant funds, house agreement however my father is not working at the moment. I had some funds in my indian account and he has been using that

When I file his papers what shall I say in my application, shall I say he is retired and I support him?

I don't have any statement that m sending some money regularly as I had some savings in my indian account and they have been using that as and when needed.

Can you please advise what is the best thing to mention in application. thanks so much