שלום וברכה הרב שליט”א Following on from my previous question regarding maaser on an inheritance, my understanding is that there will be statutory tax to pay on the money and that the residue will have to be used for our own living expenses, subsidising breast cancer treatment for my wife and subsidising children and grandchildren. The Rav shelit”a should know that I will give tzedakah in any event, but do I have an obligation to specifically set aside a fixed sum calculated on the amount received or the balance that remains? If it’s calculated on the balance that remains, how do I calculate that? בברכת התורה!
Giving maaser (one tenth to tzedaka) is not an obligation, rather a custom that many follow. Giving tzedaka is a tremendous mitzva, and can be fulfilled by giving any amount, and one should try to give according to his financial ability, but some have taken on the custom to give specifically one tenth. If you do this with regards to all your income, the same would apply to an inheritance as well.
Regarding you specific situation, a person who needs the money for himself should not give maaser to tzedaka–he uses the money he receives for himself first. Sometimes even someone who is managing financially can incur an unexpected expense (such as a medical expense) which is difficult for him to cover, and in such a situation also he does not have to give maaser because again he needs the money for himself. Therefore, use the money for your own needs and expenses first. If there is extra money, then you can give some of it to tzedaka according to your ability.
Additionally, in regards to (adult) children and grandchildren, since one is not obligated to give them money, if they are having a difficult time financially and some extra money could help, any money you give them is considered tzedaka and is considered as having given maaser. More so, it is halachically preferable to give one’s tzedaka to a relative over someone else. They don’t have to feel as if they are receiving tzedaka, rather you can be a loving parent/grandparent who is helping out your kids, and all the while fulfilling the mitzva of tzedaka.
I hope this helps. If you have any more questions please feel free to ask!
All the best