I currently receive SSDI when my son turns 18 will I get his portion of the money or will I stay the same

Hi. No, when your son stops drawing his benefits it won't cause any change to your benefit rate. Spousal and child benefits paid to family members from a retired or disabled worker's record are auxiliary, or extra, benefits. They're paid in addition to the worker's benefit amount, not taken away from it. Therefore, since your son's benefits didn't cause your benefit rate to be reduced in the first place, your benefit rate won't go up when his benefit payments stop.

Best, Jerry