According to Russian legislation, it is unclear what the deceased wrote in his will and to which cat he wrote his thousands. Before the heirs of the first row (husbands, children, parents, siblings), then the second (uncles, nephews), then the third (seventh water on the acid), and if anything remains, it goes to the favorite cat.

Do not write shit. Read the laws better. If the will is made correctly, certified by a notary, and attached to it for reliability a certificate from a psychiatrist on the full capacity of a person on the date of the will - NONE will challenge anything. There is the concept of "obligatory share in inheritance" in the amount of 50% of the share laid down by law. But it only works for disabled children, disabled spouse, disabled parents, as well as dependents who were dependent on the child for at least one year (at the same time dependents who do not belong to the circle of heirs by law must also live this year together with the resting carer). The rest is a hole from the bubble. And dependents also have to prove that the deceased kept them, and did not provide one-off assistance.