I don't know if your DS has this issue too, but estimating how long something will take is a common problem that goes along with procrastination. I ask my children to estimate how long it will take them to complete various tasks (doing dishes, completing a math worksheet, coming home from practice, etc) to help them start feeling time. For things like doing dishes, we often measure by songs --- my dd estimates how many songs it will take and she tries to finish before Alexa is finished playing the songs. For homework, we set a short period timer --- if the worksheet will take and hour, we would set a timer for 15 minutes and see if the worksheet was at least 25% complete.... adjustments would be made depending on progress. The goal wasn't necessarily to beat the timer, but to develop an appreciation for how long something would take and develop the stamina to sit and get the work finished.
I do the same thing for me at work. I am a terrible procrastinator for a variety of reasons... sometimes I don't know how I want to do the work, sometimes I spend too much time on research and gathing information, sometimes I am not interested/motivated in doing the work, sometimes I just don't appreciate how long it will take me to do the work. I will often set a time for 15 minutes.... and it helps me to reingage work if I became distracted or pick up the pace if I am taking too long..... there are a lot of things I am good at doing... managing my time is not one, but setting a timer helps.... I'm working on it.....