No, a person cannot slide up a slope if the friction between their shoe and the ground becomes larger than their weight. Friction is a force that opposes relative motion between two surfaces in contact. In the case of a person standing on a slope, the force of gravity, also known as weight, acts vertically downward. The frictional force between the person's shoe and the ground acts parallel to the slope.
If the frictional force is greater than the person's weight, it means that the friction is strong enough to prevent the person from sliding down the slope due to gravity. However, it does not allow them to slide up the slope because the frictional force always acts parallel to the slope and opposes the person's attempted motion up the incline.
To move up a slope, the person needs an additional force, such as pushing against the ground or using some external means of propulsion. Friction alone cannot cause an object to move up a slope if the force of gravity is acting against it.