I think he was asking asking about VA medical care, or I may be wrong. You qualify immediately for VA care the day you leave service honorably. . .as far as I recall.
Service-connected injuries qualify you for VA payments as well as hospital coverage.
If you retire from service you can receive military retirement pay—reduced by the amount the VA assesses for your service-connected injury and that VA amount is paid (non-taxable) to you. If you are 50% or more rated, then you can receive concurrently your full military retirement AND the VA payment (non-taxable). This is the process that is taking sooooo long. . .getting your VA disability rating. Takes years.
You are wrong you can only draw 100% total! it can be split 50-50, 60-40, etc. this has been Law since at least the 1880”s.