Unfortunately, no bonds or grants can be paid after age 49 under any circumstances. Had you opened the RDSP at age 49, you could have retroactively been eligible for grants and bonds (up to a max of $10,500 a year), but at 50 you are not eligible for anything.
The reason for this is because of the 10 year clawback rule and the age of 60. If you contributed money at, say, age 51, then at age 60 you would lose that grant money because of the clawback.