Regarding the fasting on Monday, Thursday, Monday after Pesach & Succus. If it is too hard too fast all 3 days – is it better to fast until midday on each day or perhaps fast only one of the 3 days? Thank you.
This is an interesting question.
Although I see the merit in both options, I think one full fast might be more worthwhile than three “half-fasts.”
Fasting until half-day is something of a fast, but not a “proper fast,” and when the “blessing of Behab” is declared in shul the intention is for those who fast the whole day.
There is room to question whether the blessing applies only to those who fast for all three days, or whether a special blessing applies to each day, but insofar as there is some type of enactment of fasting on these days, if a person is able and willing to fast a complete fast on one of them, it appears that this is preferable: He has fulfilled the enactment for that day, and will surely receive some measure of the blessing for it.
Best wishes and much success.