Income and assets affect SSI but not SSD. Any money (and sometimes property) will be income the month received. It must be reported to the Social Security Administration. If you have it the next month, it will be an asset. It can affect your SSI eligibility. There rules are complicated, so I cannot tell you if your SSI will be reduced or eliminated. You will have to report it and let them do the calculations. Income and assets as you have described have no effect on the SSD.
You mention a cash "gift." Rather than being given cash, the person can purchase certain assets or pay certain bills for you without affecting your SSI. But .... caution! Many common bills, such as rent, food or clothing, cannot be treated this way.
Please ... if you like this idea, do not start doing it. Counsel an attorney who works with SSI every day. Perhaps your local legal services office can help.