Who does the man in the yellow suit think should be allowed to drink from the spring?

The man in the yellow suit believes that only those who can handle the consequences of immortality should be allowed to drink from the spring. He views the spring's water as a means to gain power and control, suggesting that it should be reserved for individuals who can responsibly manage the gift of eternal life. Ultimately, his self-serving motives contrast with the more cautious and ethical views of the Tuck family regarding the spring's water.