Yes they should but it should be on own terms. For example JW's welcome to visit, but any crap to me and they are out. Mother welcome to read bible and mags, no witnessing to me. My mothers in a home for the elderly and as NO jw's come to see her and I just walk out if she starts talking crap. She has learnt the hard way. Anyway the visitors she has are all worldy and as I have pointed out have been better, loyal friends than any of the JW's
So yes help your parents but have rules.