bury

Being buried next to a sinful person

Q:

1- In some Kitaabs stories are mentioned of pious people getting buried next to sinful people due to the punishment on the sinful it has effected the pious in the grave and caused the pious to get old and have white hair etc, is it proven from Quran and ahadith that burying a pious person next to a sinful person will harm the pious person in any way?

2- Is it proven from Quran and ahadith that a person who has passed away feels and knows when he is bathed, shrouded etc and who is doing it?

Burying hair

Q:

1. Must the hairs that collect on the comb/brush be buried?

2. Must the hairs that fall out when combining/brushing the hair be collected and buried?

3. Must the hair removed from the eyebrows, nose, mustache, chest, legs, etc. all be buried?

4. When having a shower/bath, hairs that fall off sometimes tangle up together around the drain. Must this be buried?