DWR isn’t one thing (like Windstopper or eVent) it just stands for Durable Water Repellent. AFAIK different manufacturers can use different methods of achieving it.
For instance, Patagonia used to coat the fibres before weaving the fabric for some of their stuff (no idea if they still do), which made it VERY durable.
I had a pair of Berghaus that lost the WR part of DWR after one outing. When I spke to Berghaus customer service they advised to reproof “using Nikwax or something”. I’ve not bought anything made by them since and don’t plan to.
Bottom line is that some DWR treatments will work better and last longer than others.
Tumble drying or ironing (on cool settings) can help to restore them (to varying degrees) but your best bet is probably to reproof the jacket.
HTH
Si