That was more by luck, John. I don't know who told your son about the assistance on Thursdays (possibly a lady boater on Wednesday afternoon), but they were unfortunately mistaken. The guaranteed assistance previously offered by C&RT had to be booked. It was no longer available after the 2019 season.
'From Date: 01/04/2019 00:00 To Date: 31/10/2019 23:59 inclusive' Assistance on the Wigan Flight, Leeds and Liverpool Canal | Canal & River Trust (canalrivertrust.org.uk)
As has previously been mentioned, volunteers are often around, but not always. As has also been mentioned, it's worth having a look at Wigan Flight Crew on Facebook.
Really pleased that you have seen an improvement in Wigan. Cheers.