If i gift cash to my relative ( listed under it department )

dear experts ,

i want to gift  my brother 1 lacs cash . can i ? or will i have to make a gift deed ?

every year i was gifting to my brother but i never made a gift deed ? will my brother face any problem ? if yes then what should i do now ? should i prepare a declaration of gift deed now ? will this deed support him ? since he is a salaried employee and and he files a itr .

suggest me .