foundation mortar turning to sand!
You can tuck point those bricks with mortar.
Use type "S" mortar with sand, You can usually buy it premixed at the lumber yard so all you have to do is add water.
Use a grout bag, (looks like a cake decorating bag) to apply the mortar to the joints. Tool the joints with a concave joint tool.
This will a little structural strength but more importantly will keep the old mortar from falling out.