This amount is not intended to be lost and be calm, any loss will cause disappointment, even a small budget. You can avoid stress if you play only part of this budget and the stakes are so insignificant that the stake will not affect your emotions. All other situations will cause stress, this is inevitable for every player. Maybe there are those who are so emotionally stable that they will not pay attention to losses, but for this you need to have a special attitude to money, and basically people are careful with it, because they know how hard this money is to earn.
Maybe a few days ago I have seen a topic like this that there a person is explaining that even he stake small amount on the gambling he said he felt fear on every bet. For those people, I think they have gambling phobia those will always have fear and get stress with every gambling even with small fund what they can afford to lose.
We need to see here whether they are actually enjoying gambling or are they just gambling for the greed of making huge profits by spending small amounts of money and are taking stress from that. If this is the case, I think it is better for them not to gamble. Because it will only increase their hypertension and they will not be entertained at all.