Will being a direct support staff help me in my application to Nursing School???

It all depends on your school. Some schools give points on your admission score for having previous CNA work, but probably not any other healthcare work other than a licensed position such as CNA or a tech. My school did not give points for having job experience, but there was a high school program here called "Tri Tech" that you could get 2 points if you completed. The staff says rarely do people even have these points because you have to have completed high school in our area. I would say take a good look at the applications you will be completing.

As a DSP myself , as well as an LPN. I can tell you that it really didn't help at all.

No it is not relevant to nursing at all in the eyes of a Nursing School. You should be CPR and First Aide trained but other than that "nursing" care is pretty much limited to assisting with ADLs.

A DSP can usually do 1 of 3 things. Respite, Habilitation, or Attendant Care. Attendant and Hab are similar to CNA work. With Attendant care you do ADLs. Which is pretty much helping them get dressed and ready for the day or for bed. Light house keeping and some assisted shopping. Respite is pretty much babysitting. You allow caregivers time off and "watch" or entertain the person. Habilitation is usually working on goals and skills that have been set forth. For example your person may be working on stranger danger, money management, or simply brushing their own teeth.

While these skills are helpful, and working with this population is rewarding, and will get you used to interacting in a professional manner with clients, CNA experience is more relateable and usually where nursing staff is hired from.